HA  Nj) BOORS  for  Students  and  General  Readers 


ZOOLOGY 

OF  THE   VERTEBRATES 

MACALISTER 


REESE    LIBRARY 

BIOLOGY 


UNIVERSITY   OF   CALIFORNIA. 


Received. 


t* 


HANDBOOKS  for  Students  and  General  Readers 
IN  SCIENCE^  LITERATURE,  ART,  AND  HISTORY. 


Messrs.  HENRY  HOLT  &  Co.  have  begun  the  publication  of 
a  Series  of  brief  Hand-books  in  various  departments  of  know- 
ledge. They  will  be  suitable  for  the  use  of  persons  already 
possessing  the  usual  elements  of  education  who  wish,  in  the 
shortest  possible  time,  to  get  a  general  knowledge  of  the  sub- 
jects treated  in  the  Series.  The  principal  fields  they  seek  to 
occupy  are  in  the  upper  classes  of  public  and  private  schools, 
and  among  mature  persons  of  little  leisure  who  wish  to  enlarge 
or  revise  their  knowledge. 

The  subjects  and  authors,  so  far  as  selected,  are  as  follows  : 

Architecture.     By  RUSSELL  STURGIS,  A.M.,  Professor  of  Architecture 

and  the  Arts  of  Design,  in  the  College  of  the  City  of  New  York. 
The  Studio  Arts,     By  ELISABETH  WINTHROI-  JOHNSON. 
Astronomy.     By  R.  S.  BALL,  LL.D.,  F.R.S.,  Astronomer   Royal   for 

Ireland. 

Botany.    By 

Chemistry.     By 

English  Language.     By  THOMAS  R.  LOUNSBURY,  Professor  in  Yale 

College. 

English  Literature.    By 

French   Literature.     By  FERDINAND  BOCHKK,  Professor   in  Harvard 

University. 

Geology.    By 

German  Literature.    By 

Health.     By 

Jurisprudence.      By  JOHNSON  T.    PI.ATT,    Professoi     in    the    Law 

Department  of  Yale  College . 
Music.     By 

Physical    Geography.       By   CLARENCE   KING,    U.S.    Geologist    in 

charge  of  survey  of  the  4oth   Parallel. 
Physics.    By 

Political  Economy.     By  FRANCIS  A.    WALKEK,  Ph.D.,  Professor  in 
Vale  College. 

Zoology.     By  A.   MC-ALISTER.    M.D.,    Professor    in    the   University   of 
Dubl.n. 


'  N.  B. — Any  books  in  the  series  that  may  be  the  work 
of  foreign  authors  will  be  specially  revised  for  America  by  some 
one  among  the  best  American  authorities. 


HANDBOOKS  for  Students  and  General  Readers. 

ZOOLOGY 

OF    THE 

VERTEBRATE  ANIMALS 


BY 

ALEX.    MACALISTER,   M.D. 

Professor  of  Zoology  and  Comparative  Anatomy  in  the 
University  of  Dublin. 


Specially  Revised  for  American  Students 


A.  S.   PACKARD,  JR.,  M.D. 

Professor  of  Natural  History  in 
Brown  Unh>ersity 


NEW   YORK 
HENRY   HOLT   AND    COMPANY 

1878 


HZ, 

SlOLOGi 


G 


COPYRIGHT,  1878, 

BY 
HENRY    HOLT    &    CO. 


I'RINTRD   BY   TROw's    PRINTING    AND   BOOKBINDING    CO.,  NEW   YORK. 


EXPLANATORY. 


THIS  Series  is  intended  to  meet  the  requirement  of 
brief  text-books  both  for  schools  and  for  adult  readers 
who  wish  to  review  or  expand  their  knowledge. 

The  grade  of  the  books  is  intermediate  between  the 
so-called  "primers"  and  the  larger  works  professing 
to  present  quite  detailed  views  of  the  respective  sub- 
jects. 

Such  a  notion  as  a  person  beyond  childhood  re- 
quires  of  some  subjects,  it  is  difficult  and  perhaps 
impossible  to  convey  in  one  such  volume.  Therefore, 
occasionally  a  volume  is  given  to  each  of  the  main 
departments' into  which  a  subject  naturally  falls — for 
instance,  a  volume  to  the  Zoology  of  the  vertebrates, 
and  one  to  that  of  the  invertebrates.  While  this  ar- 
rangement supplies  a  compendious  treatment  for  those 
who  wish,  it  will  also  sometimes  enable  the  reader 
interested  in  only  a  portion  of  the  field  covered  by  a 
science,  to  study  the  part  he  is  interested  in,  without 
getting  a  book  covering  the  whole. 

Care  is  taken  to  bring  out  whatever  educational 
value  may  be  extracted  from  each  subject  without  im- 


vi  Explanatory. 

peding  the  exposition  of  it.  In  the  books  on  the 
sciences,  not  only  are  acquired  results  stated,  but  as 
full  explanation  as  possible  is  given  of  the  methods  of 
inquiry  and  reasoning  by  which  these  results  have 
been  obtained.  Consequently,  although  the  treatment 
of  each  subject  is  strictly  elementary,  the  fundamental 
facts  are  stated  and  discussed  with  the  fulness  needed 
to  place  their  scientific  significance  in  a  clear  light, 
and  to  show  the  relation  in  which  they  stand  to  the 
general  conclusions  of  science. 

Care  is  also  taken  that  each  book  admitted  to  the 
series  shall  either  be  the  work  of  a  recognized  author- 
ity, or  bear  the  unqualified  approval  of  such.  As  far 
as  practicable,  authors  are  selected  who  combine 
knowledge  of  their  subjects  with  experience  in  reach- 
ing them. 


PREFACE 


IT  has  been  the  Author's  design  in  this  volume  to 
present  in  as  simple  a  form  as  possible  the  leading 
characters  of  Vertebrate  Animals.  All  unnecessary 
technicalities  have  been  dispensed  with,  and  explana- 
tions have  been  given,  either  in  the  text  or  in  the 
glossary,  of  such  terms  as  have  been  unavoidably 
used. 

In  a  practical  science  such  as  Zoology,  it  is  only 
by  the  examination  of  specimens  that  any  knowledge 
of  the  science  worth  acquiring  can  be  obtained,  and 
the  function  of  a  book  is  to  assist  in  practical  study. 
This  has  been  borne  in  mind  in  compiling  these 
pages.  Great  care  has,  moreover,  been  taken  to  select 
only  such  facts  for  discussion  as  are  of  fundamental 


viii  Preface. 

importance.  As  types  of  the  different  classes  of  ver- 
tebrated  animals  are  easily  obtainable,  the  pupil  is 
recommended  to  verify  these  facts  for  himself. 

ALEXANDER  MACALISTER. 

ANATOMICAL  MUSEUM, 

UNIVERSITY  OF  DUBLIN, 
Oct.  2,  1877. 


CONTENTS. 


CHAPTER  I. 

CHARACTERS  OF  VERTEBRATE  ANIMALS.   ACRANIA. 

PAGE 

The  Vertebrate  Body— Notochord— Skeleton— Amphioxus     .      I 
CHAPTER  II. 

CRANIOTA. 

The  Brain  and  Skull— Visceral  Arches— Limbs— Ribs— Liver— 
Heart— Segmentation       .......      6 

CHAPTER   III. 
CLASS  i.  PISCES  (FISHES). 

General  Characters— Scales— Fins— Lateral  Line — Skeleton — 
Brain— Gills  and  Breathing— Swimming  Bladder— Eggs   .    XI 

CHAPTER   IV. 

ORDER  I.  LAMPREYS.   ORDER  2.  SHARKS. 

Lampreys  or  Marsipobranchs— Selachia  or   Sharks— Placoid 

Scales— Egg  Capsules — Sawfishes — Skates        .        .        .22 

a 


Contents. 


CHAPTER  V. 

ORDER  3.    GANOID   FISHES.      ORDER  4.    BONY  FISHES. 

ORDER   5.    DIPNOI. 

PAGB 

Ganoids  —  Scales  —  Isinglass  —  Teleostei — Sub-order,  Physo- 
stomi  —  Sub-order,  Anacanthini  —  Sub-order,  Acantho- 
pteri — Sub-order,  Pharyngognathi  —  Sub-order,  Lopho- 
branchii— Sub-order,  Plectognathi— Dipnoi  .  .26 


CHAPTER  VI. 

CLASS  2.    AMPHIBIA. 

General  Characters— Respiration— Skeleton    .        .        •        •    34 
CHAPTER  VII. 

CLASSIFICATION   OF  AMPHIBIA. 

Order  i,  Gymnophiona— Labyrinthodonts— Order  2,  Urodela— 
Caducous  and  Perennial  Gills — Order  3,  Anura        .        .    37 

CHAPTER   VIII. 

CLASS   3.     REPTILES. 

General  Characters  .  ,40 


CHAPTER  IX. 

LIZARDS  AND  SNAKES. 

Order  i,  Lacertilia— Chamseleons— Order  2,  Ophidia  or  Snakes 
—Venomous  Snakes  and  their  Poison-Apparatus      .        .    42 

CHAPTER  X. 

TORTOISES  AND   CROCODILES. 
Order  3,  Chelonia  or  Tortoises— Order  4,  Crocodilia        .        .    49 


Contents.  xi 

CHAPTER  XI. 

CLASS  4.     AVES   (BIRDS). 

PAGE 

General  Characters — Feathers  and  Feather  Tracts — Skeleton — 
Muscles — Digestive  Organs — Heart  and  Lungs — Eye — 
Eggs 52 

CHAPTER   XII. 

CLASSIFICATION  OF  BIRDS. 

Sub-class  i,  Ratidse — Sub-class  2,  Carinatae — Order  i,  Psittaci 
or  Parrots — Order  2,  Coccygomorphae  or  Cuckoos — Order 
3,  Pici  or  Woodpeckers — Order  4,  Macrochires  or  Swifts 
and  Humming-Birds — Order  5,  Passeres  or  Perching  Birds 
— Order  6,  Raptores  or  Birds  of  Prey  .  .  .  .62 

CHAPTER  XIII. 
CLASSIFICATION  OF  BIRDS  (continued}. 

Order  7,  Gyrantes  or  Pigeons — Order  8,  Rasores  or  Scraping 
Birds  —  Order  9,  Grallae  or  Snipes  and  Cranes — Order 
10,  Ciconise  or  Storks — Order  n,  Lamellirostres  or  Ducks 
and  Geese — Order  12,  Longipennes  or  Gulls — Order  13, 
Steganopodes  or  Pelicans — Order  14,  Pygopodes  or 
Penguins  and  Auks 69 

CHAPTER   XIV. 

CLASS   5.     MAMMALIA. 

General  Characters — Laws — Skeleton  —  Teeth  —  Dental  For- 
mulae   74 

CHAPTER  XV. 

CLASSIFICATION   OF  MAMMALS. 

Order  i,  Monotremata — Order  2,  Marsupialia  or  Kangaroos   .    79 


xii  Contents. 

CHAPTER  XVI. 

PLACENTAL  MAMMALS. 

PAGE  - 

General  Characters— Order  3,  Edentata  or  Ant-eaters  and 
Armadillos— Order  4,  Bradypoda  or  Sloths— Order  5, 
Sirenia  or  Manatees— Order  6,  Ungulata  or  Hoofed 
Animals  —  Unsymmetrically-toed  Ungulates  —  Even-toed 
Ungulates — Bunodonts — Ruminants 85 

CHAPTER  XVII. 

PLACENTAL  MAMMALS   (continued}. 

Order  7,  Cetacea  or  Whales— Order  8,  Pinnipedia  or  Seals — 
Order  9,  Carnivora  or  Flesh-Eaters—Dogs—Cats—Bears — 
Order  10,  Hyracoidea— Order  n,  Rodentia— Order  12, 
Proboscidea  or  Elephants 99 

CHAPTER  XVIII. 

Order  13,  Prosimii  or  Lemurs — Order  14,  Insectivora,  Moles, 

Hedgehogs,  etc.-— Order  15,  Chiroptera  or  Bats        .        .113 

CHAPTER  XIX. 

Order  16,  Primates — Marmosets— American  Monkeys — Old- 
World  Monkeys — Man — Races  of  Man  .  .  .  .118 

INDEX  and  GLOSSARY .  125 


L  I  B  R  A  R  Y 

I   XI  VKMSIT  V   OF 

CAUKOUNLA. 
VERTEBRATA. 


CHAPTER  I. 

CHARACTERS  OF  VERTEBRATE  ANIMALS.   ACRANIA. 

i.  Introductory. — The  animals  which  make  up  the 
sub-kingdom  Vertebrata  are  the  fishes,  reptiles,  birds, 
and  quadrupeds ;  and  as  they  present  to  us  a  greater 
number  of  interesting  points  in  structure,  function,  and 
habits  than  all  the  other  sub -kingdoms  put  together, 
and  as  they  are  for  the  most  part  of  large  size  and  of 
complex  organisation,  they  require  a  more  careful  and 
detailed  study  than  do  the  animals  which  make  up  the 
other  sub-kingdoms.  On  this  account,  Vertebrata, 
though  in  reality  constituting  only  a  subdivision  equi- 
valent to  any  of  the  other  sub-kingdoms,  such  as 
Mollusca,  Polystomata,  or  Vermes,  are  yet  often  treated, 
and  naturally  so,  as  if  they  equalled  all  the  other  sub- 
kingdoms  collectively. 

2.  General  characters  of  vertebrate  animals. — 
Every  vertebrate  animal  possesses  in  the  centre  of 
its  body  an  axis  or  rod  of  cartilage,  which  forms  a 
B 


2  Vertebrata. 

skeleton  or  support ;  below l  is  a  longitudinal  body- 
cavity,  containing  the  organs  of  digestion,  circulation, 
respiration,  &c. ;  above  is  a  second,  smaller,  longitu- 
dinal cavity  or  canal,  in  which  lie  the  brain  and 
spinal  marrow,  the  central  organs  of  the  nervous 
system ;  these  send  out  laterally  along  their  whole 
extent  numerous  pairs  of  nerve-cords  to  supply  the 
different  parts  of  the  body.  Thus  on  cross-section 
the  body  of  a  vertebrate  animal  appears  like  two 
tubes,  the  smaller  being  above  the  larger,  and  the 
cartilaginous  axis  appears  in  the  middle  of  the 
horizontal  partition  which  divides  them  from  each 
other. 

In  the  young  conditions  of  the  tunicated  worms 
there  is  an  approach  to  this  arrangement,  but  in  these 
the  gristly  rod  does  not  extend  sufficiently  far  for- 
ward to  separate  the  neural  (or  nervous  system- 
holding)  and  visceral  cavities. 

To  the  central  axis  of  cartilage  the  name  notochord 
is  given,  and  it  is  enveloped  in  a  sheath  of  several 
layers.  In  the  majority  of  vertebrates  the  notochord 
is  present  only  as  a  temporary  and  transitory  structure, 
for,  in  the  process  of  growth,  parts  of  its  sheath  enlarge 
and  encroach  on  the  axis  itself,  so  as  to  obliterate 
it  eventually  in  whole  or  in  part.  These  enlarge- 
ments begin  in  the  form  of  a  succession  of  paired 
lateral  thickenings  along  the  whole  length  of  the 
sheath,  which  extend  above  and  below  the  notochord, 
and  become  converted  into  rings  around  it,  and 
ultimately  by  extension  inwards  they  become  discs. 

1  The  animal  is  supposed  to  be  placed  with  its  length  hori- 
zontal and  its  mouth  forwards. 


General  Characters  of  Vertebrates.  3 

The  chain  of  these  rings  or  disks,  around  or  replacing 
the  notochord,  which  forms  the  axis  in  the  adult  stage 
of  all  but  the  lowest  of  the  vertebrates,  is  called  the 
vertebral  columii,  and  each  disk,  with  the  parts  im- 
mediately joined  to  it,  is  called  a  vertebra  (fig.  2). 

Each  vertebra  has  attached  to  it  behind  a  ring  or 
arch  (made  up  of  two  lateral  projections  or  processes) 
which  surrounds  the  spinal  marrow,  and  forms  the 
wall  of  the  neural  cavity.  This  arch  is  called  the 
neural  arch. 

The  mouth  opens  at  the  foremost  end  of  the  body 
in  all  vertebrates,  and  communicates  internally  with  a 
cavity  called  the  pharynx,  on  whose  walls,  directly  or 
indirectly,  the  blood-vessels  are  arranged  for  the 
purposes  of  respiration.  This  part  of  the  digestive 
canal J  is  pierced  by  slits  at  some  period  in  the  life  of 
each  vertebrate. 

Below  the  pharynx  is  a  narrow  part  of  the  diges- 
tive canal,  called  the  (esophagus,  which  passes  between 
the  spinal  column  above  and  the  heart  below,  and 
leads  into  the  stomach,  from  whence  the  intestinal 
canal  is  continued,  to  open  at  the  posterior  end  of 
the  body  ;  directly  below  the  stomach  the  duct  of  the 
liver  opens  in  all  vertebrates,  and  this  organ  is 
peculiar  in  this  sub-kingdom,  in  that  the  vein  which 
conveys  the  impure  blood  back  from  the  digestive 
organs  enters  this  gland  and  breaks  up  within  it  into 
a  network  of  fine  vessels,  which,  reuniting,  pass  back 
from  hence  to  the  heart.  The  vessel  which  thus 

1  The  digestive  or  alimentary  canal  is  a  tube  traversing 
the  whole  length  of  the  body,  in  which  the  food  is  digested, 
and  its  nourishing  part  taken  into  the  b.lpod. 


4  Vertebrata. 

conveys  the  blood  from  the  alimentary  canal  to  the 
liver  is  called  the  venaportce. 

3.  Primary  divisions  of  vertebrates  (headless 
form). — There  are  two  primary  divisions  of  vertebrate 
animals  ;  the  first  of  these  includes  only  one  form,  and 
that  the  smallest  and  simplest  in  the  sub-kingdom, 
remarkable  principally  for  its  extremely  simple  organ- 
isation. This  little  creature  is  named  the  lancelet,  or 
technically  the  Amphioxus  lanceolatus^  and  is  so  called 
on  account  of  its  lancet-like  shape,  and  from  its  being 
pointed  at  both  ends.  It  is  a  small,  flattened,  fish-like 
animal,  about  an  inch  and  a  half  long,  about  a  quarter 
of  an  inch  in  depth  and  an  eighth  in  thickness,  found 
in  sandbanks  in  our  own  seas.  It  has  been  taken 
in  abundance  off  the  coasts  of  North  Carolina  and 
Florida,  off  the  S.W.  coast  of  Ireland,  in  the  Mediter- 
ranean, and  in  the  Indian  and  Pacific  Oceans. 

This  animal  has  no  head,  and  the  notochord 
stretches  from  the  front  to  the  hinder  point ;  the 
neural  canal  and  its  enclosed  spinal  marrow  likewise 
extend  for  the  whole  length.  The  mouth  is  a  longi- 
tudinal slit,  bordered  with  stiff,  bristle-like  filaments ; 


Diagram  tf  Amphioxus. 

a,  mouth ;    b)f,g,  respiratory  region ;    c,  body  cavity  ;    */,  liver  ;   *,  heart ; 
£-/,  digestive  canal ;  /,  notochord  ;  me,  spinal  marrow. 

and  the  pharynx  has  many  lateral  slits  in  its  wall, 


The  Lancdet.  5 

through  which  the  water  which  enters  the  mouth 
escapes  into  the  space  between  the  wall  of  the  body 
and  that  of  the  pharynx.  To  this  space  the  name 
'  atrium '  is  given,  and  it  opens  externally  by  a  median 
pore  or  outlet  placed  on  the  under  edge,  and  in  front 
of  the  end  of  the  intestine  (fig.  i,/). 

The  liver  is  a  simple  sac,  and  the  heart  is  a  single  di- 
lated tube(^),  like  that  of  some  worms;  it  sends  branches 
backwards  to  the  pharyngeal  wall,  one  along  each  slit, 
and  these  join  dorsally  below  the  notochord,  making 
a  dorsal  aorta  or  large  blood-vessel,  which  gives  off 
branches  to  the  different  parts  of  the  body. 

Though  there  is  no  brain,  yet  two  of  the  foremost 
of  the  many  nerves  emitted  from  the  spinal  marrow 
supply  structures  which  may  be  regarded  as  rudimen- 
tary sense-organs.  Thus  there  is  in  the  middle  of  the 
foremost  end  of  the  animal  a  small  pit,  possibly  an 
organ  of  smell,  and  two  or  more  lateral  pigment- spots 
in  front  of  and  above  the  mouth,  which  may  be  organs 
of  sight.  There  is  a  narrow  membranous  fringe  or  fin 
around  the  tail,  but  there  are  no  limbs,  and  the  blood 
is  colourless. 

The  division  of  Vertebrata  which  contains  this  sin- 
gularly aberrant  form  is  named  Acrania  (headless),  to 
distinguish  it  from  that  which  includes  the  entire  re- 
maining series,  which  is  called  Craniola  (head-bearing), 


6  Vertebrata. 

CHAPTER  II. 

CRANIOTA. 

4.  General  characters  of  head-bearing  vertebrates. 

The  head-bearing  vertebrates  are  characterised  by 
the  enlargement  of  the  anterior  end  of  the  central 
axis  of  the  nervous  system  into  a  series  of  swellings 
which  collectively  make  up  the  brain.  To  contain 
this  brain  the  fore  part  of  the  neural  canal  is  enor- 
mously dilated,  and  its  walls  are  converted  into  a 
gristly,  membranous,  or  bony  case,  called  the  skull, 
and  in  this  part  of  the  body  the  organs  of  sense  are 
chiefly  seated.  The  brain  in  its  simplest  form  con- 
sists of  three  thick-walled  cavities  in  a  series  from 
before  backwards,  the  walls  of  the  three  being  named 
respectively  the  fore,  mid,  and  hind  brain.  The  rest 
of  the  neural  canal  behind  the  skull  remains  as  a 
narrow  tube  enclosed  in  the  canal,  which  is  bounded 
by  the  neural  arches  of  the  vertebrae.  In  the  sides 
of  the  wall  of  the  cranial  or  skull  cavity  the  organs  of 
the  special  senses  are  placed  in  a  series  from  before 
backwards  ;  foremost  of  them  is  the  organ  of  smell ; 
secondly,  that  of  sight;  thirdly,  that  of  hearing.  Each 
of  these  organs  consists  primarily  of  a  pouch  of  skin 
bulging  towards  the  inside  of  the  body,  and  receiving 
a  nerve  from  the  brain.  Passing  out  from  the  brain 
there  are  also  other  nerves,  which  are  distributed  to  the 
parts  of  the  foremost  end  of  the  body.  Around  these 
organs  and  nerves  the  cartilage  which  forms  the  primi- 
tive skull  becomes  disposed  so  as  to  protect  them;  and 


Visceral  A  rches.  7 

when,  as  is  often  the  case,  the  cartilage  becomes  con- 
verted into  bone,  the  several  pieces  of  which  the  osseous 
skull  consists  are  so  grouped  around  these  nerves  and 
sense  organs  that  the  bony  cranium  appears  as  if  its 
bones  were  arranged  in  a  succession  of  segments. 
These  have  been  mistaken  for  true  vertebral  divisions, 
but  are  really  due  to  a  secondary  grouping  of  parts  in 
the  course  of  growth,  and  are  not  primary  morpho- 
logical elements.  Appended  to  the  under  or  mouth 
side  of  the  cranium,  and  to  the  fore  part  of  the 
vertebral  column,  we  find  a  series  of  lateral  arches, 
which  unite  below  in  the  medial  line,  and  thus 
close  in  the  sub- vertebral  cavity  in  front.  To  these 
arches  the  name  '  visceral  arches/  is  given  ;  and  very 
often  between  these  arches  there  are  slits  opening 
inwards  ;  these  are  called  visceral  slits.  The  number 
of  these  arches  varies  in  many  vertebrates,  but  there 
may  be  as  many  as  ten  or  twelve.  The  foremost  is  in 
front  of  the  part  of  the  skull  which  begins  at  the  front 
end  of  the  notochord  (for  this  structure  does  not  in 
craniotes  extend  beyond  the  region  of  the  mid-brain), 
and  its  two  elements  pass  forwards  in  the  middle 
line  to  unite  in  front;  to  these  the  name  cornua 
trabeculce  is  given.  The  second  arch  lies  behind, 
below,  and  a  little  outside  the  cornua  trabeculse,  and 
forms  part  of  the  deeper  or  palatine  portion  of  the 
upper  jaw  in  most  vertebrates  (or  the  whole  upper 
jaw  in  sharks) ;  its  lower  end  forms  the  lower  jaw,  or 
parts  thereof.  The  third  or  hyoid  arch  is  that  bony 
system  on  which  the  tongue  is  based  ;  and  the  suc- 
ceeding ones  can  be  easily  distinguished  in  fishes  as 
ie  arches  of  bones  which  bear  the  gills,  but,  except 


th< 


8  Vertebrata. 

the  foremost  of  this  set,  the  others  are  rudimental  in 
the  higher  animals.  The  visceral  slit  between  the  first 
and  second  of  these  arches  is  the  mouth ;  the  other 
visceral  slits  remain  either  as  the  gill  fissures  in  fishes, 
or  else  become  closed  at  an  extremely  early  period 
of  embryonic  life.  The  remnant  of  the  first  pair  of 
visceral  slits  behind  the  mouth  we  find  in  the  form  of 
the  ear  passages  in  higher  vertebrates.  These  visceral 
arches  never  extend  backwards  behind  the  heart. 

5.  Limbs  and  ribs. — Vertebrate  animals  have 
never  more  than  four  limbs,  which  are  placed  two  in 
front  and  two  behind.  The  fore  limbs  are  usually 
placed  a  short  way  behind  the  head  ;  the  hind  limbs 
at  or  immediately  behind  the  posterior  end  of  the 
visceral  cavity.  Each  limb  has  a  bony  or  gristly  axis 
or  skeleton,  and  this  consists  of  two  parts — first,  a 
girdle  or  half-zone  of  bone,  which  is  embedded  in  the 
lateral  muscles,  and  is  often  attached  to  the  vertebral 
column  ;  secondly,  a  limb  ray  or  projecting  part  made 
up  of  several  sets  of  cartilages  in  a  series.  Some 
vertebrates,  like  whales  and  some  lizards,  have  only 
two  fore  limbs  and  no  hind  limbs ;  others,  like  boas 
and  pythons,  have  rudimentary  hind  limbs  and  no  fore 
limbs;  others,  like  most  of  the  snakes,  have  no  limbs  at 
all.  These  limbs  are  always  turned  towards  the 
haemal  or  ventral  side  of  the  body. 

In  the  wall  of  the  visceral  cavity,  following  the 
visceral  arches,  but  quite  separate  from  them,  there 
are  usually  long  slender  bones,  jointed  at  the  back 
to  the  vertebral  column,  and  forming  supports  for 
the  wall  of  this  space.  These  bones  are  named 
ribs,  and  the  part  of  the  body  surrounded  by  them 


Ribs  and  Secreting  Organs. 


FIG.  2. 


Diagram  of  a  vertebra,  with  its 
body  (5,),  rib  (7),  and  breast  bone  (6). 


is  called  the  thorax ;  the  region  between  the  thorax 
and  the  head  is  called  the  neck — a  very  short  space 
in  fishes  and  whales,  long 
in  many  birds.  The  part 
of  the  vertebral  column 
which  projects  behind  the 
visceral  cavity  is .  named 
the  caudal  or  tail  region, 
and  in  it  there  are  usu- 
ally V-like  bony  arches, 
suspended  to  the  lower 
surface  of  the  vertebral 
bodies,  within  which  a 
caudal  blood-vessel  is  pro- 
tected. 

6.  Secreting  organs. — All  vertebrate  animals  of 
this  division  have  a  solid  glandular  liver  for  secreting 
the  bile,  an  important  fluid  used  in  the  process  of 
digestion.  They  have  all  red  blood,  the  colour  de- 
pending on  the  presence  of  certain  minute  coloured 
corpuscles.  The  circulation  of  the  blood  is  maintained 
by  a  muscular  heart,  which  never  possesses  fewer  than 
two  chambers,  one  of  which  is  for  the  collection  and 
reception  of  the  blood  from  the  veins,  and  is  called 
the  auricle  •  the  other,  which  is  named  the  ventricle, 
propels  the  blood  into  the  large  blood-vessels  or  aortic 
arches,  of  which  there  are  usually  (in  some  period  of 
life  at  least)  more  than  three  pairs. 

In  vertebrates  the  lining  membrane  of  the  mouth 
(which  is  named  the  mucous  membrane\  clothing  the 
upper  and  lower  jaws,  and  sometimes  the  similar 
membrane  over  other  bones,  developes  processes  or 


ro  Vertcbrata. 

papillae,  which  become  converted  into  a  very  hard 
kind  of  bones  for  the  purpose  of  seizing  and  dividing 
their  food  ;  these  are  known  as  teeth.  In  higher 
forms  these  become  rooted  in  the  subjacent  bones, 
but  in  all  cases  they  arise  as  papillae  of  the  mucous 
membrane. 

The  products  of  waste  (which  is  constantly  taking 
place)  are  got  rid  of  by  means  of  certain  purifying 
organs.  The  skin,  by  means  of  its  glands,  removes 
some  of  these  effete  matters ;  so  do  certain  areas  of 
the  pharynx,  richly  supplied  with  blood-vessels  from 
the  aortic  arches,  and  which  are  called  the  respiratory 
organs.  There  are  also  developed  certain  glandular 
tubes  in  the  hinder  portion  of  the  visceral  cavity,  of 
the  same  nature,  and  built  on  the  same  plan,  as  the 
segmental  tubes  of  worms,  which  eliminate  from  the 
blood  the  nitrogenised  waste  products  ;  these  organs 
are  called  kidneys. 

7.  Primary  and  secondary  segments. — In  the 
body  of  a  vertebrate  animal  there  is  to  be  seen  the 
remains  of  a  primary  segmentation  into  a  chain  of 
successional  divisions  ;  thus  many  organs  or  parts 
are  repeated  in  a  series,  such  as  the  vertebrae,  the 
nervous  system,  the  muscle  masses  (as  can  be  seen 
in  fishes),  and  the  tubes  which  constitute  the  kidney. 
At  the  same  time  there  is  such  a  tendency  to  con- 
centration noticeable  that  this  segmental  symmetry  is 
only  to  be  seen  in  the  lower  forms,  or  in  the  embryonic 
stages  of  the  higher,  secondary  modes  of  aggregation 
of  parts  masking  completely  the  original  systems  of 
segments.  For  example,  while  in  the  embryo  the 
primitive  vertebrae  can  be  distinguished  clearly  from 


Cephalization.  \  i 

each  other,  in  the  adult  what  appear  to  be  the  verte- 
bral segments  are  really  due  to  a  secondary  cleaving 
occurring  in  a  later  stage,  after  the  originally  separate 
primary  segments  have  become  fused. 

As  we  ascend  in  the  scale  of  complexity  among 
vertebrates,  we  find  as  a  rule  that  the  head  becomes 
more  and  more  highly  organised,  and  that  there  is  a 
tendency  towards  the  concentration  of  its  elements, 
and  that  the  fore  parts  of  the  body  become  more  and 
more  subservient  to  it.  This  reaches  its  climax  in  man, 
where  we  find  the  anterior  pair  of  limbs  entirely  set 
apart  to  wait  on  the  head. 

There  are  five  classes  of  vertebrate  animals — fishes, 
amphibians,  reptiles,  birds,  and  mammals. 


CHAPTER  I£T»  V /> 

CLASS    I,    PISCES  (fS^HEsW/OTr 


8.  General  characters  of  fishes.— Fishes 
tute  the  first  and  simplest  class  of  the  head-bearing*  *. 
vertebrates,  and,  like  the  simplest  forms  of  all  the 
other  sub-kingdoms,  they  are  aquatic  in  habit,  and 
all  their  organs  are  adapted  for  a  watery  home. 
Thus  in  shape  they  are  for  the  most  part  of  an 
elongated  flattened  outline,  pointed  in  front,  tapering 
behind,  so  as  to  afford  as  little  resistance  as  possible 
in  traversing  the  water  ;  the  fore  part  of  the  body,  or 
head,  is  joined  to  the  trunk  directly,  without  the  inter- 
vention of  a  narrow  neck,  and  to  the  hinder  ex- 


12 


Vcrtebrata. 


tremity  of  the  vertebral  column  is  appended  a  flattened 
tail,  which,  by  moving  like  a  scull  or  screw-propeller, 
can  drive  the  body  forward.  The  limbs  are  also,  in 
fishes,  developed  into  fanlike  bars,  the  fins. 

9.  Scales. — The  surface  of  the  body  in  fishes  has 
only  a  scanty  epidermis^  or  outer  layer  of  skin,  which  is 
generally  of  a  mucous  or  slimy  consistence;  beneath  this 
is  the  demits^  or  inner  skin,  whose  surface  consists  of 
numerous  thin,  flattened  scales.  These  structures,  so 
characteristic  of  fishes,  are  composed  of  bony  plates, 
which  are  ossifications  of  flat  dermal  processes,  often 
containing  or  bearing  little  tooth-like  points,  composed 
of  the  same  material  as  true  teeth.  In  some  fishes,  like 
sharks,  the  entire  scale  consists  of  this  dentine  or  tooth 

FIG.  3. 


Placoid  scale  of  dog-fish  (vertical  section  magnified). 
a,  enamel  layer  ;  b,  dentine  of  spine  on  scale. 

structure  (fig.  3)  ;  in  others  the  bony  element,  which 
forms  around  the  tooth,  covers  or  entirely  supersedes 
the  dentinal,  but  in  its  essential  nature  the  coating  of 
scales  or  dermal  exoskeleton  of  fishes  may  be  regarded 
as  consisting  of  or  containing  ossified  papillae,  which 
in  their  structure  are  identical  with  the  tissue  of  ordi- 


Scales  and  Fins.  1 3 

nary  teeth.1     Many  scales  are  of  beautiful  forms,  and 
they  vary  very  much  in  outline  and  surface,  some- 

FIG.  4. 


Cycloid  scale  of  roach  magnified  ;  seen  in  section  A,  and  on  surface  B. 

times  being  flat  and  smooth-edged  (fig.  4),  or  else 
spinose,  ridged,  or  comblike  (fig.  5).  These  structures 
can  be  examined  and  their  varieties  observed  with  the 
aid  of  a  pocket-lens.  The  scales  of  the  pike,  sole, 
and  perch  are  especially  characteristic  forms. 

10.  Fins. — Along  the  middle  line  of  the  body  of  a 
fish  there  are  usually  developed  extensions  of  the  dermal 

1  It  would  perhaps  be  more  correct  to  say  that  teeth  are 
really  in  nature  a  special  set  of  dermal  papillae  of  the  same 
nature  as  those  which  cover  the  surface  of  the  skin  in  some 
fishes,  ?nd  which,  covering  the  jaw  arches,  are  set  apart  for 
grasping  and  dividing  food  ;  but  the  relationship  is  put  con- 
versely, as  the  tooth  form  is  the  more  familiar. 


14  Vertebrata. 

exoskeleton  in  the  form  of  median  fins.     Of  these  one 
extends  along  the  upper  or  dorsal  edge,  and  is  named 
FIG  the  dorsal  fin,  consisting  of  a  suc- 

cession of  soft  and  branched  or 
spiny  and  hard  fin-rays  connected 
by  membrane.  The  other  is  pre- 
sent on  the  under  or  ventral  side 
of  the  body  behind  the  terminal 
opening  of  the  intestine ;  this  is 
called  the  anal  fin.  These  median 
fins,  though  apparently  single  and 

Ctenoid  scale.  D     .    r  r      .         J 

central,  are  in  reality  composed  of 
two  lateral  layers  placed  in  close  apposition. 

11.  Sense-organs  of  the  lateral  line. — Along  the 
line  of  greatest  convexity  of  each  side  of  the  body 
of  a  fish  there  is  a  lateral  line,  extending  from  be- 
hind  the  eye   to   the  side   of  the  tail.      This   con- 
sists of  a  row  of  scales,   each  pierced  by  a  minute 
tube   leading  into  a   small  simple  or  branched  sac 
filled  with  a  gelatinous  material,  in  which  the  extremity 
of  a  nerve  is  embedded.     These  are  organs  of  sense, 
and  are  probably  capable  of  being  impressed  by  several 
forms  of  vibration. 

12.  Backbone  and  tail. — The  vertebral  column  of 
fishes  usually  consists  of  a  chain  of  biconcave  vertebral 
bodies,  bearing  on  their  upper  surfaces  neural  arches 
which  are  surmounted  by  long  neural  spines.     On  the 
under  side  the  vertebrae  bear  ribs  towards  the  front, 
and  V-shaped  bones  towards  the  hinder  part  of  the 
body.     The  hindmost  of  the  tail  vertebrae  may  either 
gradually  diminish  to  a  point,  as  in  the  African  mud- 
fish (fig.  14),  or  they  may  undergo  modification,  being  re- 
placed by  a  rodlike  bone  which  turns  sharply  upwards, 


The  Sole.  1 5 

as  in  the  tails  of  most  of  the  bony  fishes.    The  median 
fin  is  continued  around  the  tail  end  of  the  vertebral 


i6 


Vertebrata. 


column,  and  sometimes  appears  as  a  simple  uniform 
fringe  evenly  distributed  around  the  pointed  vertebraj 
axis,  or  else  the  whole  caudal  area  of  the  vertebral 
column  becomes  upturned  and 
the  tail  fin  forms  a  large  lobe 
on  the  under  surface  of  the 
axis  while  simply  margining  the 
end  of  the  caudal  vertebrae  ; 
such  a  tail  is  spoken  of  as»  an 
unequally  lobed  tail.  When,  as 
in  bony  fishes,  the  extremity  of 
the  spinal  column  becomes  con- 
verted into  a  single  bone,  then 
the  fin  borne  by  it  is  usually 
an  evenly  bilobed  tail,  such  as 
•  that  of  a  herring  or  salmon 
or  sole.  It  is,  however,  an  in- 
(  tere  sting  fact  in  relation  to  this 
that  the  young  fry  of  the  salmon 
or  other  bony  fish  has  origi- 
nally a  tail  of  the  unevenly 
lobed  character,  which  by  the 
'  shortening  of  the  upper  part, 
and  the  expansion  of  the  lower 
lobe,  becomes  even,  as  we  find 
it  in  the  adult. 

In  the  simplest  fishes  the 
notochord  persists  through  life, 
and  such  fishes  have  generally  a  uniformly  fringed 
tail,  as  in  the  lampreys. 

The  structure  of  the  skull  differs  in  the  various 
subdivisions  of  the  class  :  in  some  it  is  a  simple  carti- 


Skull  of  Fishes.  17 

laginous  box,  as  in  lampreys  and  sharks;  in  others 
this  cartilaginous  box  is  covered  and  protected  by  a 
series  of  bony  dermal  plates,  as  in  the  sturgeon,  or 
the  whole  skull  may  be  made  up  of  a  number  of 
closely  articulated  and  perfectly  united  bony  pieces 
as  in  the  cod  (fig.  8).  In  this  case  it  must  be  re- 
membered that  these  bones  are  of  a  twofold  nature — 
first,  the  ossified  pieces  of  the  cartilage  of  which  the 
primitive  skull  consists,  and  which  surrounds  the  dif- 
ferent apertures  and  nerves,  forming  principally  the 
lateral  walls  of  the  skull ;  secondly,  the  ossified  plates 
of  membrane  which  are  the  equivalents  of  the  dermal 
bony  plates  of  the  sturgeon,  and  which  chiefly  make 
up  the  roof  and  floor  bones. 

Besides  the  skull  or  brain-case  proper,  the %  head  of 
a  fish  consists  of  four  other  series  of  bones,  as  can  be 
seen  in  fig.  8.  These  are,  first,  those  of  the  upper  jaw 
arch,  sometimes  seven  in  number  on  each  side ; 
secondly,  those  of  the  lower  jaw  arch,  sometimes  four 
or  five  pairs  ;  thirdly,  those  of  the  gill  arches,  four,  five, 
or  six  pairs  of  arches  on  each  side,  each  consisting  of 
about  four  pairs  of  bones,  and  bearing  the  gills  These 
three  series  are  chiefly  ossifications  in  the  system  of 
visceral  arches  before  referred  to.  Besides  these,  there 
is  a  fourth  group  of  bones,  those  of  the  operculum  or 
gill  cover,  which  overlap  and  cover  the  gill  arches ; 
of  these  there  are  four  or  more,  making  up  the  gill 
cover  on  each  side.  It  is  thus  not  to  be  wondered  at 
that  the  skeleton  of  the  head  of  a  fish  presents  an 
appearance  of  great  complexity. 

The  limbs  of  fishes  are  converted  into  fins,  and  of 
these  there  are  usually  two  pairs.  The  fore  limbs,  or 
c 


18 


Vertebrata. 


pectoral  fins,  are  placed  directly  behind  the  head,  to 
which  indeed  the  shoulder  girdle  is  in  most  fishes 
united  by  small  dermal  ossifications.  The  hind  limbs 
are  called  the  ventral  fins,  and  are  rarely  as  well  de- 


Skull  of  Cod. 

3,  supra-occipital  bone  ;  4,  opisthotic  ;  8,  post-temporal :  n,  frontal ;  9, 
parasphenoid  bone  ;  g,  g;  sub-orbital  bones  ;  22,  premaxilla  ;  21,  maxilla  ; 
24,  pterygoid  ;  28,  hyomandibular ;  29,  articular  piece  of  lower  jaw  ;  23, 
dentary  bone  ;  39,  40,  41,  43,  hyoid  arch  ;  44,  branchio-stegal  rays ;  34, 
35>  36,  37,  opercular  bones. 

veloped  as  the  fore  limbs,  and  the  pelvic  girdle  is 
seldom  attached  to  the  vertebral  column.  The  fins 
are  of  use  in  directing,  the  motion  of  fishes,  while  the 
tail  is  the  principal  organ  of  propulsion. 


Brain  and  Heart  of  Fishes. 


FIG.  9. 


13.  Internal  organs  of  fishes. — The  brain  of 
fishes  (fig.  9)  is  small,  not  filling  the  cranial  cavity. 
It  consists  of  a  succession  of  little  knobs  or  ganglia 
arranged  in  a  chain  from  before  backwards.  Of 
these  the  foremost  are  connected  with  the  sense  of 
smell,  the  second  consist 
of  the  fore- brain  hemi- 
spheres or  cerebrum,  the 
third  are  the  optic  lobes 
from  which  the  nerves  of 
sight  arise,  the  fourth  con- 
stitute the  mid-brain  and 
the  fifth  the  hind  brain. 

Beneath  and  behind 
the  head  lie  the  gills  (fig. 
10),  which  consist  of  nume- 
rous vascular  fringes  ar- 
ranged in  platelike  layers 
attached  to  the  visceral 
arches,  and  bathed  by  the 
water  which  enters  the 
mouth  and  escapes  through 
the  visceral  slits.  The  heart 

situated  in  the  middle  Brain  of  Cod. 

f   What  We  might    Call    the  /,  nerves  of  sight;  k,  nerves  of  smell; 

a,  foremost  lobe  of  brain  ;  c,  se- 

throat,  a  Very  Short  distance  cond    lobe  or  cerebrum  ;  /  cere 

i      -i  •     j        ,-,            ,                     .  bellum;  h,  hind  brain  or  medulla 

behind       the       lOWer       jaw.  oblongata  ;  m,  fifth  pair  of  nerves  ; 

This    nrcrnn     rnnQktQ    r»f    i  «,  nerves  of  hearing  ;  0,  ninth  pair 

Organ     COnSlStS    OI    a  of  nerves;/,  tenth  or  vagus  nerve. 

in-walled  auricle,  receiv- 

g  the  veins  which  convey  to  it  the  impure  blood 
from  the  body,  and  a  large  thick- walled  ventricle  for 
propelling  the  blood  into  the  gills.  This  latter  is 

C  2 


20 


Vertebrate. 


FIG.  10. 


sometimes  prolonged  at  its  outlet  into  a  conical  part 

full  of  valves,  called  the 
arterial  cone,  which  ends 
in  the  large  main  blood- 
vessel, or  aorta.  The 
arterial  cone  is  well  de- 
veloped in  sharks. 

Sometimes,  as  in 
most  of  our  common 
fishes,  the  aorta  at  its 


A,  the  aortic  bulb  ;  H,  heart  ;  B, 
branchial  arches  ;  b,  branchial 
veins  retaining  the  blood  to  A, 
the  aorta ;  v,  v,  the  veais. 

B  shows  the  structure  of  one  of  the 
branchial  arches,  with  its  ap- 
pended gill  filaments,  bc>  The 
blood  from  the  aortic  bulb 
passes  through  B,  the  branch- 
ial artery,  is  aerated  in  the  fila- 
ments &:,  collected  and  returned 
by  b,  the  branchial  vein,  into  A, 
the  dorsal  aorta. 


Diagram  of  the  circulation  in  a  fish. 


Circulation  in  Fishes.  21 

commencement  is  swollen  into  an  aortic  bulb,  from 
which  come  off  at  least  three  pairs  of  branchial  or 
gill  arteries  ;  these  pass  in  the  form  of  arches,  right 
and  left,  to  the  gills,  and  there  break  up  into  fine 
branches  in  the  soft,  fringe-like  folds.  Here  the 
blood,  being  exposed  to  the  air  dissolved  in  the  water, 
absorbs  oxygen  and  gives  out  carbonic  acid,  and  is 
thus  purified. 

The  purified  blood,  returning  from  the  gills  by  the 
branchial  veins ,  enters  the  dorsal  vessel  or  aorta, 
which  sends  it  to  the  different  organs  of  the  body  to 
supply  the  viscera. 

The  blood  of  fishes  is  generally  of  the  same 
temperature  as  the  medium  wherein  they  live,  or  only 
slightly  warmer,  and  hence  it  usually  feels  cold  to 
the  touch.  It  contains  corpuscles,  or  little  micro- 
scopic bodies,  of  an  oval  shape  and  with  a  central 
nucleus. 

Though  the  respiration  of  fishes  is  accomplished 
by  means  of  the  air  which  is  dissolved  in  water,  yet 
it  is  supplemented  in  some  of  them  by  direct  exposure 
of  the  gills  to  the  atmosphere,  and  some  fishes  are 
killed  if  prevented  from  rising  to  the  surface. 

In  most  fishes  there  is  a  large  sac  filled  with  air, 
placed  beneath  the  vertebral  column  at  the  anterior 
part  of  the  body  cavity,  and  communicating  by  a  duct 
with  the  digestive  organs.  This  is  called  the  swimming- 
bladder,  or  the  air-bladder,  and,  by  expanding  or 
compressing  it,  the  fish  can  rise  or  sink  in  the  water. 
This  sac  commences  its  existence  in  the  embryo  as 
an  outgrowth  from  the  neck  end  of  the  alimentary 
canal. 


22  Vertebrata. 

Fishes  are  oviparous,  that  is,  their  .young  are 
produced  from  eggs,  and  for  the  most  part  they  are 
enormously  prolific.  The  egg-organ  of  the  cod  some- 
times contains  over  a  million  eggs,  and  some  other 
fishes  are  equally  fruitful ;  the  eggs  are  of  small  size, 
and  contain  very  little  food  yolk.  The  majority  of 
fishes  are  marine  ;  those  found  in  fresh  water  are,  as 
a  rule,  simpler  in  organisation  and  retain  many  of  the 
embryonic  characters  of  the  class.  About  13,000 
different  species  of  fish  are  known,  and  they  are 
divided  into  five  orders. 


CHAPTER   IV. 

ORDER  I,  LAMPREYS  j  ORDER  2,  SHARKS. 

14.  Order  1,  Marsipobranchii  (Lampreys). — 
This,  the  most  lowly  organised  order,  consists  of 
wormlike,  limbless,  scaleless  fishes  with  no  lower 
jaw,  a  circular  suctorial  mouth,  a  persistent  noto- 
chord,  and  gills  in  the  form  of  lateral  pouches.  They 
are  also  remarkable  among  fishes  for  having  circular 
blood  corpuscles. 

The  most  familiar  examples  are  the  little  fresh- 
water lamprey,  the  large  sea  lamprey,  and  that  curious 
parasite  the  glutinous  hag,  which,  by  means  of  its 
large,  jagged  tooth,  bores  its  way  into  the  body  of  the 
cod,  ling,  or  other  large  fish,  and  lives  therein,  feeding 
on  the  juices  of  its  prey.  In  all  these  there  is  but 


Lampreys  and  Sharks.  23 

one  median  pitlike  nostril,  and  the  hag  is  remarkable 
among  fishes  for  having  a  passage  of  communication 
between  the  bottom  of  this  pit  and  the  posterior  part 
of  the  cavity  of  the  mouth.  No  such  communication 
exists  in  other  fishes,  in  which  the  nose  is  a  simple 
depression  or  cavity  on  the  surface  of  the  head,  lined 
by  a  plaited  mucous  membrane  and  crossed  over  by 
a.  bridge  of  skin.  The  teeth  in  lampreys  are  horny 
and  conical ;  they  are  shown  in  fig.  n. 

FIG.  IT. 


Head  of  lamprey  dissected. 


«,  I,  c,  cartilages  of  the  mouth  ;  d,  e,f,g,  h,  muscles  attached 
to  the  cartilages. 


The  name  Marsipobranchii  is  given  to  this  group 
on  account  of  the  pouchlike  nature  of  the  gills,  which 
are  in  six  or  seven  pairs,  arranged  in  two  lateral  rows, 
and  open  by  small  holes  on  the  surface. 

15.  Order,  2,  Selachia  (Sharks). — The  second 
order  includes  the  sharks  and  rays,  the  largest  indi- 
viduals in  the  entire  class  of  fishes  ;  but,  notwith- 
standing their  size,  these  exhibit  in  respect  to  many 
points  of  organisation  what  may  be  considered  as 


24  Vertebrata. 

elementary  characters— that  is,  they  display  in  their 
permanent  state  points  of  structure  which  other  more 
specialised  fishes  present  only  in  the  embryonic  stages. 
They  are  for  the  most  part  marine,  and  the  skeleton 
remains  almost  entirely  cartilaginous  and  never  be- 
comes truly  ossified.  The  notochord,  however,  rarely 
persists,  being  generally  replaced  by  an  axis  of  bicon- 
cave, often  calcified,  cartilaginous  disks  or  vertebral 
bodies. 

The  jaws  in  sharks  are  usually  placed  beneath,  not 
at  the  front  of,  the  prominent  snout,  and  they  are  both 
cartilaginous,  being,  in  fact,  two  parts  of  a  visceral  arch. 
The  gills  are  symmetrical  lateral  plates  of  vascular 
membrane,  interposed  between  pouches  which  have 
a  row  of  holes  or  slits  on  each  side,  opening  super- 
ficially on  the  side  of  the  neck,  and  internally  by  a 
row  of  perforations  into  the  pharynx. 

The  entire  surface  of  the  dermis  is  covered  with 
toothlike  papillae,  composed  of  true  tooth-tissue  or 
dentine,  and  these  over  the  jaw  arches  are  large  and 
developed  into  functional  teeth,  which  are  sometimes 
of  formidable  size  and  proportions.  There  are  several 
rows  of  these,  and  as  they  are  gradually  worn  away 
with  use,  they  replace  each  other  from  within  out- 
wards. This  form  of  dermal  scales  on  the  surface  of 
the  body  is  named  placoid  (fig.  3). 

The  vertebral  axis  is  prolonged  into  the  upper 
lobe  of  the  tail,  which  thus,  on  account  of  the  large 
size  of  the  lower  lobe,  belongs  to  the  unevenly  lobed 
or  heterocercal  type,  not  like  the  uniform  marginal 
fringe  of  the  lampreys.  The  fins  are  often  armed 
with  single,  strong,  and  sometimes  serrated  spines, 
which  are  used  as  weapons  of  offence. 


Sharks. 


The  heart  in  sharks  has  a  long  arterial  cone.  The 
intestine,  though  short,  is  very  capacious,  and  has  the 
extent  of  its  inner  surface  in- 
creased enormously  by  means 
of  a  long  spiral  fold  of  its 
lining  mucous  membrane, 
which  stretches  throughout 
almost  its  whole  extent.  Like 
the  lampreys,  sharks  are  de- 
void of  a  swimming-bladder. 

Some  sharks  are  vivipa- 
rous (that  is,  produce  their 
young  alive) ;  in  others  the 
young  are  extruded  within 
curious  horny  tendril-bearing 
cases,  which  are  often  picked 
up  along  the  sea-shore,  and 
are  commonly  called  i  mer- 
maids' purses.' 

The  commonest  examples 
of  this  order  are  the  dog-fishes, 
sharks,  and  rays.  One  of  the 
largest  forms  is  the  great  bask- 
ing shark  of  the  North  At- 
lantic ;  this  fish  is  not  at  all 
uncommon  on  the  west  coast 
of  Ireland,  where  it  is  called 
the  sun-fish,  and  is  often  cap- 
tured for  its  oil.  It  also  oc- 
curs, though  but  rarely,  on  the 
American  coast.  It  often  ex- 
ceeds thirty  feet  in  length,  and  a  specimen  of  this 
size  will  yield  ninety  gallons  of  oil  from  its  liver.  The 


Beak  of  saw-fish  seen  fr  m  1  e- 
low,    showing    its    mout 
nostrils,  and  lateral  teeth. 


26  Vertebrate. 

gigantic  Rhinodon  of  the  Indian  Ocean  has  been  met 
with  sixty  feet  in  length.  The  hammer-headed  shark, 
with  its  extraordinary  bilobed  head,  and  the  saw-fish 
(fig.  12),  with  its  long,  flattened,  bony  snout  bearing  a 
row  of  strong,  sharp  teeth  on  each  side,  are  also  ex- 
amples of  the  order. 

The  skates,  or  rays,  are  remarkable  for  their  flat- 
tened form,  due  largely  to  the  enormous  size  of  the 
pectoral  fins.  One  form,  rarely  found  in  British  seas, 
though  common  in  the  Mediterranean,  is  the  torpedo 
or  electric  ray,  which  has  near  its  head  two  large 
electric  batteries,  whereby  the  fish  can  give  severe 
electric  shocks ;  these  organs  are  joined  to  the  brain 
by  large  nerves,  and  consist  of  closely  apposed 
columnar  elements,  which  morphologically  are  con- 
sidered to  consist  of  extremely  modified  muscular 
tissue. 


CHAPTER  V. 

ORDER   3,   GANOID    FISHES  ;    ORDER   4,    BONY   FISHES  ; 
ORDER    5,  DIPNOI. 

1 6.  Order  3,  Ganoidei. — The  living  fishes  of  this 
group  are  very  few  (about  thirty),  and  most  of  them 
are  inhabitants  of  rivers  or  of  lakes  but  in  former 
times  they  were  apparently  numerous  and  rich  in 
species,  as  the  fossil  remains  of  six  hundred  species 
are  already  known.  They  are  characterised  by  pos- 
sessing ganoid  scales — that  is,  brightly  polished  plates 


Bony  Fishes.  27 

covered  with  a  lamina  of  an  enamel-like  substance. 
They  have  likewise  unsymmetrical  tails  and  a  ventri- 
cular arterial  cone.  The  gills  are  free,  and  are  placed 
on  bony  gill-arches,  under  cover  of  opercula  or  gillr- 
flaps,  not  in  pouches  nor  on  plates.  Some,  like  the 
sturgeons,  have  a  persistent  notochord  ;  others,  like 
the  Californian  bony  pike,  have  fully  ossified  verte- 
bral bodies.  The  other  forms  included  in  this  order 
are  the  Polypterus  of  the  Nile  and  the  reed  fish  of 
Calabar,  as  well  as  several  rare  and  curious  American 
species.  Many  of  the  fossil  forms  were  of  large  size 
and  of  extraordinary  shapes  ;  their  remains  abound 
in  some  of  the  old  red  sandstone  formations.  All 
living  forms  have  a  swimming-bladder,  which  in  the 
sturgeon  yields  the  isinglass 1  of  commerce. 

17.  Order  4,  Teleostei. — This  is  by  far  the  largest 
group  of  fishes,  and  includes  all  those  which,  like  our 
common  fishes,  possess  a  bony  skeleton  with  bicon- 
cave vertebral  bodies.  The  tail  consists  of  two  even 
lobes  supported  on  a  sharply  upturned  and  conti- 
nuously ossified  end  of  the  vertebral  column  (fig.  6). 
The  body  has  usually  a  uniform  coating  of  smooth  or 
ribbed  or  spinose  scales,  which  rarely  have  an 
enamelled  surface.  The  gills  consist  of  free,  usually 
comblike,  filaments  on  bony  branchial  arches  (fig.  10), 
arranged  under  the  flaplike  gill-cover  or  operculum. 
There  is  no  arterial  cone,  the  mouth  of  the  ventricle 
having  but  one  row  of  valves. 

This  order  of  fishes  is  divided  into  the  following 
six  sub-orders  : — 

1  Isinglass  is  a  corruption  of  the  German  Hausenblase,  from 
Hauscn,  a  sturgeon, and  Blase,  a  bladder — i.e.  sturgeon's  bladder. 


28  Vertebrata. 

SUB-ORDER  i,  PHYSOSTOMI,  or  those  in  which  the 
swimming-bladder  communicates,  in  the  adult,  with 
the  digestive  canal  by  means  of  a  duct.  In  these 
also  all  the  fin  rays  are  soft  and  jointed,  except 
perhaps  the  foremost  ray  of  each  fin,  which  may  be 
spinose  from  a  fusion  of  its  separate  elements.  In 
this  group  are  included  the  pike,  carp,  goldfish, 
herring,  salmon,  trout,  and  most  of  our  fresh-water 

FIG.  13. 


Viscera  of  herring. 

a,  oesophagus  ;  b)  c,  stomach,  with  its  appendages,  d;  e,  intestine  ; 
/,  duct  of  the  swimming-bladder,  k  ;  7t,  ovary. 

fishes,  such  as  the.  barbel,  tench,  roach,  ide,  minnow, 
&c.  Some  of  these  physostome  fishes  have  no 
ventral  fins — for  example,  the  eels,  a  few  of  which,  like 
the  prettily  marked  Helen's  eel  of  the  Mediterranean, 
are  also  devoid  of  pectoral  fins.  One  genus  of  eels, 
the  Gymnotus,  of  the  large  rivers  of  South  America, 
has  a  powerful  electric  organ,  formed  of  some  of  the 
modified  body  muscles.  This  apparatus  stretches 
along  almost  the  entire  body,  and  as  the  fish  some- 
times reaches  the  length  of  six  feet,  the  organ  is  of 
very  considerable  size,  and  is  capable  of  giving  violent 
electric  shocks.  Two  other  genera  of  physostome 


Flat  Fishes.  29 

fishes  have  also  electric  organs  ;  one  of  these  is  a 
genus  of  river  fishes — Malapterurus,  from  the  Nile — 
the  other— Mormyrus,  also  African — has  a  very  small 
electric  organ  near  the  tail. 

Some  fishes  belonging  to  a  curious  marine  group 
of  this  sub-order— the  Scopelidae — are  remarkable  not 
only  for  the  brilliancy  of  their  lustre,  but  for  the  fact 
of  their  possessing  several  pairs  of  accessory  eyes  on 
the  gill  covers.  One  other  species  of  physostome  fish — 
Amblyopsis  which  inhabits  the  -Mammoth  Cave  of 
Kentucky — is  remarkable  for  the  rudimentary  condition 
of  its  eyes,  which  are  covered  with  a  layer  of  skin, 
and  are  hence  functionless. 

SUB-ORDER  2,  ANACANTHINI. — This  subdivision 
includes  those  soft-finned  fishes  which  have  either  no 
swimming-bladder  or  have  one  that  has  no  duct.  In 
these  not  even  the  foremost  fin-rays  are  spinous,  but 
all  are  soft-jointed  and  branched.  They  are  for  the 
most  part  marine,  and  include  many  of  the  common- 
est of  our  sea  fishes,  such  as  the  cod,  haddock, 
whiting,  saith,  lithe,  ling,  &c.  One  interesting  group 
— that  of  the  flat  fishes — is  remarkable  for  the  want 
of  symmetry  displayed  in  the  body,  which  is  ex- 
tremely compressed,  and  the  animal  in  progression 
invariably  lies  on  one  side,  swimming  with  one  side 
up  and  the  other  directed  downwards.  These  fishes 
usually  keep  near  or  on  the  bottom,  and  the  upper 
side  is  usually  dark  or  coloured  while  the  lower  side 
is  white.  To  accommodate  the  structures  of  the 
animal  to  this  extraordinary  habit,  the  eyes  are  twistod 
round  both  to  the  one  side  of  the  head — viz.  that 
which  is  uppermost — so  are  the  nostrils,  and  the 


3O  Vertebrata. 

mouth  is  also  usually  awry,  so  as  to  give  the  greatest 
amount  of  facility  of  swallowing  consistent  with 
position.  As  in  this  distorted  position  the  dorsal 
and  anal  fins  are  disposed  as  lateral  fringes,  they 
functionally  replace  the  paired  fins  as  directors  of 
motion,  and  hence  the  pectoral  and  ventral  fins  are 
usually  small  or  deficient.  One  interesting  feature  in 
these  fishes  is  that  their  embryos  at  a  very  early  stage 
are  perfectly  symmetrical,  and  gradually  develope  the 
one-sided  torsion  as  growth  progresses,  the  displaced 
eye  having  been  traced  by  observers  in  its  curious 
pilgrimage  around  the  front  of  the  obliquely  growing 
head  from  the  under  to  the  upper  side.  The  turbot, 
plaice,  flounder,  sole,  dab,  and  fluke  are  well-known 
examples  \  the  largest  species  inhabiting  our  seas  is 
the  halibut,  which  sometimes  has  been  known  to 
attain  the  weight  of  over  500  pounds.  Another 
curious  point  is  noteworthy — viz.  that  though  in  each 
genus  the  side  to  which  the  eyes  are  displaced  is 
usually  constant,  yet  erratic  reversed  examples  are 
occasionally  met  with.  Thus  while  in  the  flounder 
and  plaice  the  eyes  are  usually  on  the  right,  in  such 
reversed  cases  they  are  found  looking  to  the  left ; 
such  abnormalities  are  easily  understood  by  the  light 
of  the  embryonic  development  of  the  group. 

One  genus  of  fish  of  this  sub-order,  named 
Fierasfer,  is  parasitic  within  the  bodies  of  certain 
sea-cucumbers,  or  holothurians,  and  star-fishes,  and 
is  found  in  the  Indian  Ocean. 

SUB-ORDER  3,  ACANTHOPTERI.  —  Spiny -finned 
fishes  with  a  ductless  swimming-bladder,  or  else  none. 
This  is  the  most  numerous  and  most  specialised  group 


Spiny -finned  Fishes.  3 1 

of  bony  fishes.  The  scale-clothing  of  this  class  is 
usually  remarkable  for  the  comblike  or  spiny  surface 
and  hinder  margin  of  each  scale,  whereby  they  are 
distinguished  from  the  circular  smooth  scales  of  the 
physostome  fishes.  The  most  familiar  examples  are 
the  perches  of  our  streams ;  the  bull-heads  and  gur- 
nards, known  by  their  spiny  heads,  found  along  our 
coasts  ;  the  sticklebacks,  so  interesting  on  account  of 
the  nests  constructed  by  the  males  for  the  protection 
of  the  young  ;  the  mullets,  which  have  the  singular 
property  of  changing  colour  when  they  are  dying  ;  the 
mackerels,  bi  earns,  braizes,  blennies,  gobies,  &c. 

Some  of  these  fishes  are  laterally  compressed,  like 
flat  fish,  but  without  showing  any  distortion  of  the 
heads,  such  as  the  John  d'Ory  and  Archer  fishes  ;  the 
latter  are  East  Indian  fishes,  and  owe  their  name  to 
their  habit  of  shooting  at  flies  by  forcibly  ejecting 
drops  of  water  from  their  long  snouts.  The  sword- 
fish,  which  sometimes  attains  the  length  of  sixteen  feet, 
is  closely  allied  to  the  mackerel,  and  is  remarkable  for 
the  long,  swordlike  upper  jaw.  The  common  lump- 
sucker,  the  little  red  or  brown  Lepadogaster  of  En- 
gland, and  the  tropical  Remora  are  remarkable  as 
being  provided  with  sucking  disks,  whereby  they  can 
adhere  with  great  tenacity  to  foreign  bodies.  Fistularia 
(the  tobacco-pipe  fish)  is  remarkable  for  his  long 
tubular  snout,  as  is  also  the  allied  trumpet- fish. 
Trachinus  (the  weever)  is  said  to  be  able  to  inflict 
poisonous  wounds. 

There  are  three  aberrant  groups  of  spiny-fmned 
fishes,  which  constitute  the  remaining  three  sub-orders. 

The  first  of  these,  or  sub-order  4,  is  called  Pharyu 


32  Vertebrate. 

gognathi,  or  pharynx- jaw-bearing  fishes,  on  account  of 
the  presence  of  a  single  medial  tooth-bearing  bone  in 
the  pharynx,  made  up  of  the  united  lateral  remains  of 
one  of  the  hindmost  of  the  visceral  arches,  which  does 
not  bear  gills.  The  flying  fishes,  distinguished  by 
their  long  pectoral  fins  ;  the  gar-pikes  and  parrot 
fishes  ;  the  cunners  and  tautogs,  so  common  along 
our  shores,  are  the  most  familiar  examples  of  the 
group.  They  are  small  or  moderate-sized  tishes,  with 
spiny  fins,  and  often  with  strong  conical  teeth  in  the 
jaws. 

Sub-order  5  consists  of  the  sea  horses  and  pipe 
fishes,  which  differ  from  all  other  fishes  in  having  the 
gill  filaments  in  symmetrical  clusters  or  tufts  on  the 
gill  arches,  not  in  comblike  plates  ;  hence  they  are 
called  Lophobranchii,  or  tufted-gilled  fishes.  Their 
bodies  are  clad  with  bony  plates,  and  are  often  of 
eccentric  angular  shapes.  They  have  no  ribs,  their 
jaws  are  toothless,  and  the  males  in  some  species 
are  provided  with  pouches  on  the  front  of  the 
abdomen,  into  which  they  collect  the  eggs  on  their 
being  laid  by  the  females,  and  within  which  the 
young  are  hatched. 

The  sixth  sub-order,  Plectognathi,  or  soldered  jaws, 
consists  of  spiny-finned  fishes  in  which  the  bones  of 
the  upper  jaw  are  consolidated  together  instead  of 
remaining  separate ;  these  are  the  singular  globe-fishes, 
whose  spiny  bodies  are  capable  of  inflation,  and  whose 
bare,  ivory-like  teeth  give  them  such  a  remarkable 
appearance.  The  file  fishes  also,  with  their  rough, 
branched  spines  and  tough  skin  and  the  angular  box- 
fishes,  which  belong  to  this  order,  are  likewise  among 


Mud  Fishes. 


33 


the  most  singularly  shaped  of  FlG- x 

tropical  fishes.  One  remarkable 
species — the  sun  fish — a  large 
globular  fish  with  an  extraordi- 
narily thick  skin,  sometimes 
reaches  the  weight  of  400 
pounds. 

1 8.  Order  5,  Dipnoi.— This, 
the  last  and  in  some  respects 
most  interesting  order,  includes 
three  living  fishes,  which  form 
a  transition  to  the  next  class. 
These  fishes  differ  from  all  the 
foregoing  in  having  the  swim- 
ming-bladder developed  as  an 
accessory  respiratory  organ  ;  the 
blood  returning  from  it  being 
received  into  a  small  additional 
auricle  of  the  heart  placed  to 
the  left  of  the  main  auricle. 
They  have  a  covering  of  horny 
scales,  and  the  alimentary  canal 
has  a  spiral  valve.  They  also 
exhibit  the  peculiarity  of  pos- 
sessing tubular  nasal  passages  i 
which  perforate  the  upper  lip, 
opening  into  the  mouth.  One 
of  the  fishes  of  this  order  is  the 
African  mud  fish,  or  Protopterus 
of  the  Gambia;  another  is  the 
Lcpidosiren  (fig.  14),  of  South 
America  ;  and  the  third  is  the  (The  mud  fish,  Lepidosiren\ 

D 


34  Vertebrata. 

Ceratodus,  of  the  rivers  of  Queensland.  In  several 
respects  these  fishes  present  characteristics  which  are 
identical  with  the  embryonic  conditions  of  many  of 
the  higher  groups  of  animals.  The  characters  of  the 
skeleton  can  be  seen  in  fig.  7. 


CHAPTER  VI. 

CLASS    2,   AMPHIBIA. 

19.  Characters  of  Amphibia.-— The  class  Am- 
phibia,  to  which  we  are  structurally  conducted  by  the 
last  order  of  fishes,  consists  of  cold-blooded  animals, 
usually  of  small  size.  This  is  at  present  the  poorest 
in  species  of  all  the  classes  of  vertebrata,  yet,  as  in  the 
case  of  the  ganoid  fishes,  at  earlier  periods  in  the 
world's  history  the  animals  of  this  class  vastly  ex- 
ceeded their  present  representatives  in  number,  size, 
and  complexity.  Like  fishes,  they  are  characterised 
by  having  a  feeble  development  of  the  outer  skin, 
or  epidermis,  but,  unlike  them,  they  have  no  dermal 
clothing  of  scales,  and  the  surface  is  generally  smooth, 
naked,  and  often  glandular.  Some  of  them,  in  the 
embryonic  or  tadpole  stage  of  their  existence,  possess 
rudiments  of  the  system  of  sense  organs,  like  those 
of  the  lateral  line  in  fishes,  but  none  of  them  are 
retained  in  the  adult  state.  Amphibians,  moreover, 
have  no  functional  fin-rays,  though  sometimes  they 
have  marginal  membranous  fringes,  as  in  the  common 
newt  or  tadpole,  and  even  rudimentary  rays,  as  in  the 


Characters  of  A  mphibians.  3  5 

toe-webs  of  some  salamanders.  They  also  undergo 
regular  metamorphoses,  beginning  life  as  little  fish- 
like  creatures  with  large  flat  heads  and  external  gills. 
To  this  stage  the  name  tadpole  is  commonly  given. 
Then,  as  development  progresses,  the  air  sacs  (which 
correspond  to  the  swimming-bladder  in  fishes)  grow, 
become  large,  vascular,  and  capable  of  acting  as 

FIG.  15. 


Skeleton  of  frog. 

*,  skull ;  Z>,  vertebrae ;  c,  sacrum ;  d,  ilium ;  e,  urostyle  ;  /,  suprascapula  ; 
g,  humerus  ;  h,  fore-arm  bones  ;  /,  wrist  bones  ;  m,  thigh  bone  ;  n,  leg 
bones  ;  o,  elongated  first  pair  of  ankle  bones  ;  /,  q>  foot  bones. 

breathing  organs,  which  are  then  called  lungs ;  and 
ultimately,  in  the  adult  state,  a  pulmonary  or  direct 
air-breathing  system  supplants  the  gill  or  branchial 
system  of  earlier  life.  The  two-chambered  larval 
heart  at  the  same  time  becomes  three-chambered, 
developing  a  special  auricle  in  the  left  side  for  the 
reception  of  the  blood  which  has  been  purified  in 


36  Vertebrata. 

the  lungs,  and  is  returned  from  hence  into  the  heart. 
It  may  also  be  noted  that,  during  this  process  of 
development  in  the  common  frog  the  digestive  canal, 
which  in  the  tadpole  is  long  and  spirally  coiled, 
becomes  shorter  and  straighter  The  blood  of  amphi- 
bians is  remarkable  for  the  large  size  of  the  oval  red 
corpuscles  which  it  contains,  those  in  Proteus  being 
of  an  inch  in  diameter,  those  in  the  frog  being 
The  vertebral  column  in  the  simplest  of  the 
amphibians  consists  of  rudimentary  or  biconcave 
vertebrae  ;  in  frogs  (fig.  15),  however,  it  consists  of  a 
chain  of  a  few  solid  disks  whose  surfaces  fit  into  each 
other  by  ball  and  socket  joints.  Ribs  are  either  very 
short  or,  as  in  frogs,  absent.  The  skull  articulates 
to  the  foremost  vertebra  by  means  of  two  lateral  arti- 
cular surfaces  which  are  called  condyles.  The  skull 
is  also,  as  a  rule,  much  more  consolidated  than  the 
skull  in  fishes,  but  resembles  the  latter  in  having,  as 
the  most  conspicuous  bone  in  its  base,  a  long  ossifi- 
cation in  the  membrane  underlying  the  middle  of  the 
cartilage  of  the  base  of  the  skull,  which  is  known  as 
the  parasphenoid  bone,  a  bone  which  is  rudimental  or 
absent  in  all  higher  forms.  Amphibians  also  differ 
from  fishes  in  having  a  middle  ear,  closed  by  a  tym- 
panic membrane,  and  not  merely  the  internal  ear 
cavity  which  constitutes  the  ear  in  fishes.  Their  nasal 
cavities  open  posteriorly  into  the  pharynx.  They 
have  usually  four  limbs,  which  consist  of  parts  com- 
parable with  those  in  higher  animals,  and  very  unlike 
the  fins  in  fishes. 

There  are  three  orders  of  amphibians  at  present 
represented  by  living  forms  on  the  globe. 


K 

- 

CHAPTER 

CLASSIFICATION   OF   AMPHIBIA. 


^  H/         '<v 

•'        7' 


± 

20.  Order  1,  Gymnophiona.  —  A  small  group  4fV 
worm-like  forms,  with  no  limbs,  rudimental  eyes  *N 
(hence  they  are  called  C(zcilia\  which  are  found  in 
tropical  countries  burrowing  in  the  ground.  These, 
with  one  exception,  have  the  body  provided  with 
dermal  scales.  They  are  usually  marked  with  super- 
ficial rings  like  an  earth-worm,  and  range  in  size  from 
one  to  two  feet,  rarely  exceeding  this  length.  At 
present  only  a  few  species  exist,  but  many  fossil  forms 
have  been  found  which  probably  resembled  these  in 
structure. 

A  large  and  structurally  complex  order  of  fossil 
amphibians,  named  Labyrinthodonts,  formerly  in- 
habited the  earth,  which  in  some  respects  seem  to 
have  been  related  to  the  Ccecilians,  but  were  much 
larger,  and  many  of  them  were  defended  by  dermal 
coats  of  bony  mail  something  like  the  armour  clothing 
of  a  crocodile. 

21  Order  2,  Urodela.  —  Limb-bearing  amphibians 
provided  with  a  permanent  tail,  which  is  retained 
during  life.  There  are  two  sections  in  this  order,  in 
one  of  which  the  animals  retain  their  embryonic  gills 
through  their  whole  existence,  and  are  thus  peren- 
nially or  permanently  branchiate,  while  in  their  adult 
condition  they  also  possess  lungs,  which  become  de- 
veloped gradually  in  process  of  growth.  In  the  other 
section  the  gills  are  only  transitory  or  caducous, 


Vertebrata. 


wasting  and  disappearing  on  the  development  of  the 
lungs.     Of  the  former,  ox perennibranchiate  section  we 
have  interesting  examples  in  the  sirens  or  mud  eels  of 
FlG  l6  Carolina,  which  are 

provided  with  only 
two  limbs  represent- 
ing the  fore  limbs 
of  other  verte- 
brates. Another 
form,  the  proteus, 
inhabits  the  Cave 
of  Adelsberg  and 
other  caves  in  Ca- 
rinthia,  &c.,  and  is, 
like  all  other  cave- 
dwellers,  blind  and 
blanched ;  its  weak 
fore  legs  are  pro- 
vided with  three 
toes,  while  the  hind 
limbs  possess  only 
two.  The  curious 
axolotl  (fig.  1 6)  of 
Mexico  is  an  inte- 
resting form,  as  it 
has  proved  to  be  a 
permanent  tadpole 
which  in  certain 
conditions  only  un- 
dergoes its  further  metamorphosis  into  the  salamander- 
like  form  of  its  adult  state. 

Jn  some  perennibranchs  the  outer  gills  disappear, 


Diagram  of  the  axolotl,  showing  its  gills,  b, 
and  lungs,  P. 


Frogs.  39 

and  are  replaced  by  an  internal  series,  or  gills  of  the 
type  of  those  developed  in  fishes.  This  modification 
in  the  structure  of  these  organs  is  of  considerable  inte- 
rest from  a  morphological  point  of  view,  when  we  re- 
member that  in  sharks  there  are  originally  in  the 
embryo  distinct  external  gills,  which  are  lost  as  the 
shark  attains  his  more  perfect  organisation,  and  are 
replaced  by  the  permanent  gills,  which  are  formed 
directly  on  the  aortic  arches.  From  these  conditions 
it  seems  as  if  external  gills  were  a  more  primitive  or 
embryonic  form,  and  internal  gills  a  more  specialised 
modification  of  respiratory  organs.  The  amphibians 
which  show  these  internal  gills  are  the  giant  Sieboldia 
of  Japan,  which  reaches  a  length  of  four  feet,  and  the 
amphiuma  and  menopoma  of  North  America.  The 
caducibranchiate  tailed  amphibians  are  the  sala- 
manders and  newts,  the  latter  of  which  are  common 
in  our  ditches,  where  their  metamorphoses  ran  easily 
be  traced.  The  common  newt  is  interesting  on  ac- 
count of  the  bright  colours  which  it  exhibits  at  certain 
stages,  and  for  the  remarkable  dorsal  crest  which  it 
also  occasionally  possesses. 

22.  Order  3,  Anura. — The  largest  group  of  the 
Amphibia  consist  of  the  frogs  and  toads,  or  the  tailless 
forms.  In  these,  the  larva  or  tadpole  loses  during 
its  development  all  traces  not  only  of  its  gills,  but  also 
of  its  tail ;  the  hinder  limbs  are  also  in  these  more 
perfectly  developed  than  the  fore,  and  the  two  proxi- 
mal bones  of  the  ankle  are  elongated,  so  as  to  make 
what  appears  to  be  an  independent  third  portion  of 
the  hind  limb.  The  fore  arm  and  the  leg  proper  also 
differ  from  those  of  urodeles  and  of  the  higher  verte- 


4O  Vertebrata. 

brates  in  that  there  are  only  single  bones  in  these 
regions,  the  separate  bones,  radius  and  ulna,  which 
are  present  in  these  parts  of  other  vertebrates  being 
here  united.  The  frogs,  toads,  pipas,  and  tree  frogs 
are  the  most  striking  examples  of  this  order. 


CHAPTER  VIII. 

CLASS    3,    REPTILES. 

23.  Characters  of  Reptilia. — Tortoises,  lizards, 
snakes,  and  crocodiles  are  the  leading  forms  included 
in  this  large  third  class  of  vertebrate  animals,  a  class 
often  confounded  with  the  amphibians,  but  differing 
therefrom  in  many  striking  and  characteristic  respects. 
Reptiles  are  invariably  provided  with  a  very  distinct 
epidermic  clothing  of  scales  which  differ  essentially 
from  the  dermal  scales  of  the  foregoing  groups.  The 
scales  of  reptiles  being  epidermal,  and  not  parts  of  the 
dermis  or  true  skin,  are  often  shed  and  replaced,  as 
in  snakes,  and  they  are  sometimes  hard  and  thick,  as 
in  the  tortoise  shell  of  commerce  and  in  the  mail 
clothing  of  the  crocodile.  This  firm  covering  may  be 
supplemented  by  a  dermal  bony  layer,  as  in  croco- 
diles or  tortoises,  but  these  indurations  of  the  dermis 
are  never  superficial.  The  blood  is  cold  ;  the  aortic 
arches  never  bear  gills,  nor  is  there  ever  branchial 
respiration  in  any  stage  of  existence  among  the  animals 
of  this  group.  The  heart  consists  of  three  cavities, 
two  auricles  and  one  ventricle  ;  but  the  latter  is  often 


Characters  of  Rep' lies. 


FIG.  17. 


more  or  less  perfectly  divided  by  a  septum,  so  as  to 
act  as  if  it  were  a  double  chamber  (fig.  17).  There  are 
always  at  least  two  aortic  arches,  right  and  left,  which 
usually  unite  subvertebrally  to  form  one  dorsal  aorta. 
The  notochord  never  per- 
sists in  the  adult,  and  in 
most  living  reptiles  the 
vertebral  bodies  unite  witn 
each  other  by  ball  and 
socket  joints,  and  are  very 
rarely  biconcave.  The 
skull  joins  the  vertebral 
column  by  a  single  me- 
dian articular  eminence 
or  condyle,  and  there  is 
no  parasphenoid  bone, 
the  bones  of  the  middle 
of  the  base  of  the  skull 
being  developed  in  the 
cartilage  of  the  base  itself, 
not  in  the  membrane  be- 
neath the  cartilage.  The 
lower  jaw  articulates,  as 
in  the  amphibians,  with 
the  end  of  the  preceding  visceral  arch ;  and  a  bone 
at  its  extremity  called  the  quadrate  bone  is  interposed 
between  the  palatine  part  of  that  arch  and  the  skull. 

Many  reptiles  are  ovoviviparous ;  others  are  ovi- 
parous. Like  the  amphibians,  the  reptiles  at  the  present 
day,  though  still  numerous,  give  us  a  very  faint  idea  of 

Iir  former  grandeur  of  size  and  complexity.     In  the 
sozoic  age  they  held  the  same  position  on  the  globe 


Heart  of  turtle. 
H,  ventricle  ;  //,  k'.  auricles. 


42  Vertebrata. 

that  the  Mammalia  do  at  the  present  period.  Only 
four  orders  of  reptiles  are  represented  in  the  existing 
terrestrial  fauna ;  at  least  five  orders,  and  these  in- 
cluding the  giants  of  the  class,  have  perished. 


CHAPTER  IX. 

LIZARDS   AND    SNAKES. 

24.  Order  1,  Lacertilia. — The  lizards  are  scale- 
clad,  and  at  least  forelimb-bearing  reptiles,  with  a  heart 
possessing  a  single  ventricle,  and  with  a  lower  jaw  of 
firmly  united  segments.  The  eyes  are  provided  with 
movable  and  functional  eyelids,  and  the  teeth  are  not 
in  sockets,  but  are  disposed  in  rows  either  around 
the  edge  or  along  the  side  of  the  jaws. 

The  cloaca,  or  cavity  into  which  the  digestive 
canal  and  excreting  orifices  open,  has  usually  its 
outlet  placed  transversely.  Like  most  of  the  lowly 
organised  vertebrates,  lizards  display  a  remarkable 
power  in  restoring  lost  parts,  and  in  connection  with 
this  we  perceive  in  them  a  facility  for  making  their 
escape  from  capture  by  breaking  off  their  extremities. 
Thus  a  lizard  taken  by  the  tail  will  often  break  off 
that  process  and  escape,  the  fracture  taking  place 
not  between  two  of  the  vertebrae  which  make  up  the 
organ,  but  actually  through  the  middle  of  a  vertebra, 
as  there  is  a  medial  cartilaginous  plate  in  the  caudal 
vertebrae  of  some.  In  one  specimen  in  the  writer's 
possession  a  lizard  whose  tail  was  cracked,  but  not 


Lizards.  43 

broken  off,  developed  at  the  crack  an  accessory  tail, 
while  the  original  tail  yet  remained  and  became  re- 
paired at  its  injured  part,  thus  giving  a  bifid  extremity 
to  the  tail. 

Some  lizards  are  snakelike  and  ringed,  like  the 
amphisbaenas,  with  no  projecting  limb-rays,  but  in  all 
these  traces  of  the  limb  girdles  are  persistent,  although 
they  may  not  show  superficially,  as  in  the  blind  worm — 
a  pretty  and  innocent,  though  much  maligned,  native 
of  Great  Britain,  whose  scientific  name  Anguis  fragilis, 
expresses  the  brittleness  before  referred  to.  The 
common  wall-lizards  are  typical  examples  of  the  long 
fork-tongued  division  of  the  order.  The  monitors 
and  teguexins,  or  safeguards  of  the  tropics,  are  so  called 
because  they  are  supposed  to  give  warning  of  the 
presence  of  crocodiles.  They  reach  the  length  of  six 
to  eight  feet,  and  are  among  the  largest  of  living 
lizards,  although  they  are  but  pigmies  when  compared 
with  the  extinct  forms  of  which  fossil  remains  have 
been  found,  sometimes  exceeding  thirty  feet  in  length. 

The  American  iguanas  are  large-sized  lizards 
which  are  used  as  food  ;  they  usually  bear  tufted 
crests  on  the  back,  and  have  thick  short  tongues. 
Some  lizards  have  large  lateral  flaps  of  skin  :  thus  the 
frilled  lizard  of  Australia  bears  on  each  side  of  the 
neck  a  wide  fold  of  skin  like  a  ruff  or  Queen  Eliza- 
beth collar ;  others,  like  the  little  flying  dragon,  bear 
on  each  side  a  winglike  fold,  supported  on  extended 
ribs,  and  these,  together  with  the  long  conical  chin- 
pouch,  give  this  creature  a  very  extraordinary  appear- 
ance. The  appropriately  named  Moloch  horridus  of 
Australia  bristles  most  repulsively  with  conical  spines, 


44 


Vertebrata. 


as  do  many  other  genera.  The  geckos  of  India  are 
remarkable  for  the  suckers  which  they  bear  on  the 
ends  of  their  fingers,  whereby  they  can  walk  up  per- 
pendicular walls  and  along  ceilings.  The  last  group  of 
lizards,  the  chameleons,  are  interesting  for  their 
proverbial  quality  of  changing  colour,  due  to  the  ex- 
pansion and  contraction  of  certain  pigment-bearing 
connective  tissue  bodies  in  the  skin.  They  also 


FIG. 


Head  of  chameleon,  with  protruded  tongue. 

possess  circular  eyelids,  and  a  very  long  tongue  (fig. 
1 8)  capable  of  being  protruded  with  lightning-like 
rapidity. 

25.  Order  2,  Ophidia  (Snakes). — These  dreaded 
animals  may  be  regarded  in  some  respects  as  special 
modifications  of  the  lizard  type.  They  are  scale-clad 
and  limbless,  not  having  even  a  remnant  of  the 
shoulder  girdle  persistent.  The  sternum  and  sternal 
apparatus  have  also  vanished,  and  the  skeleton  consists 
of  a  long  vertebral  column,  often  of  several  hundred 
joints  or  vertebrae,  each  of  which  bears  two  ribs,  one 
on  each  side. 


Serpents.  45 

The  vertebrae  have  each  a  concavity  on  the 
anterior  side  of  each  body,  into  which  the  ball  or 
convexity  of  the  hinder  surface  of  the  foregoing  body 
fits.  There  are  also  two  pairs  of  articular  facets  on 
the  processes  of  each  vertebra,  so  that  the  entire 
spine  combines  flexibility  with  amazing  strength. 
The  ribs  are  capable  of  being  moved  forwards  and 
backwards,  and  the  ventral  surface  of  the  animal's 
body  is  covered  with  flat,  horny  shields,  into  which 
muscles  run  from  the  tip  of  each  rib.  The  rapid, 
even,  gliding  motion  in  serpents  is  accomplished  by 
the  successive  advances  of  these  ventral  scutes,  and 
the  drawing  of  the  body  forwards  towards  them,  while 
the  slightly  projecting  hinder  edges  of  the  scutes 
serve  as  fixed  points  by  catching  the  surface  of  the 
ground.  The  brain  case  is  firmly  built  up  of  sin- 
gularly united  bones ;  but  the  bones  of  the  upper  and 
lower  jaw-arches  are  loose,  united  together  by  means 
of  fibrous  tissue,  and  hence  capable  of  an  extreme 
degree  of  stretching  during  the  swallowing  of  food, 
which  these  animals  bolt  in  large  masses. 

The  teeth  are  recurved  and  solidified  to  the  jaw, 
not  set  in  sockets,  and  they  can  only  act  as  organs  of 
prehension. 

The  tongue  consists  of  a  long,  bifid  muscular  organ, 
capable  of  being  rapidly  protruded,  or  of  being  drawn 
back  into  a  sheath  when  not  in  use.  The  windpipe 
is  long  and  protected  by  complete  gristly  rings;  only 
one  lung  is  usually  large  and  developed,  the  other  is 
rudimental  or  simply  saccular,  and  they  are  never 
symmetrical.  The  digestive  canal  is  capacious  and 
short,  and  the  cloacal  opening  is  transverse.  The 


46 


Vertebrate. 


eyelids  are  confluent  and  transparent,  forming  the 
clear  glassy  surface  of  the  eye,  and  thus  giving  to  the 
serpent  the  stony,  unwinking  stare  peculiar  to  them. 

The  boas  of  the  New  World,  and  pythons  of  the 
East,  are  remarkable  among  snakes  for  their  size  and 
for  the  strength  of  their  teeth,  as  well  as  for  the  pos- 
session of  two  rudimentary  hind  limbs  in  the  form  of 
spur-like  processes  placed  one  on  each  side  of  the 
cloaca.  Some  of  these  serpents,  like  the  anaconda  of 

FIG.  19. 


Poison  fangs  showing  their  internal  hollows. 

America,  have  been  known  to  reach  the  length  of 
forty  feet,  and  even  larger  specimens  are  described. 

The  Colubrine  snakes,  such  as  the  common  Amer- 
ican striped  snake  (Eutcemia  scrtalis},  are  all  harmless 
creatures,  mostly  of  small  size,  and  having  all  the 
teeth  solid,  not  grooved. 


Poison  Fangs  of  the    Viper.  47 

26.  Poisonous  Snakes. — The  most  remarkable, 
though  not  the  most  numerous  group  of  serpents, 
are  those  provided  with  poison-fangs,  the  vipers  and 
rattlesnakes.  Of  these  the  best  known  is  the  rattle- 
snake, in  which  animal  the  epidermal  clothing  of  the 
last  few  tail-joints  is  loose,  and  consists  of  hard,  horny 
rings  loosely  embracing  each  other  ;  these  cause  the 
rattling  noise,  when  the  animal's  tail  is  shaken,  which 
nas  given  rise  to  the  name  of  this  dreaded  American 
snake.  Like  most  other  poisonous  snakes,  it  has 

FIG.  20. 


Poison  apparatus  of  rattlesnake. 
#,  poison  bag  and  duct ;  e,  i,  g,  t,  uy  muscles  of  jaw. 

a  flat  triangular  head,  and  in  its  mouth  there  can  be 
seen  the  two  long  grooved  maxillary  teeth  in  which 
are  the  channels  for  the  poison.  These  are  the  only 
large  teeth  in  the  mouth,  all  the  others  being  small 
and  obscure.  They  are  placed  far  forwards  in  the 
upper  jaw,  and  are  movable  along  with  the  movable 
maxilla,  being  bent  upwards  towards  the  palate  in  the 


48  Vertebrata. 

closed  position  of  the  mouth,while  in  the  gaping  state 
they  project,  being  arched  downwards,  ready  to  be 
inserted  into  the  victim  about  to  be  struck.  The 
groove  in  the  tooth  leads  into  a  canal  which  traverses 
the  base  of  the  poison  fang,  and  is  continued  by  a 
duct  into  a  cavity  or  sac,  which  receives  the  tubular 
ducts  of  the  poison  gland  (fig.  20).  In  the  act  of 
striking,  the  muscles  which  close  the  jaws  squeeze  the 
poison  sac  and  drive  the  poison  through  the  duct  into 
the  tooth,  and  thence  into  the  wound. 

The  poison  apparatus  is  constructed  on  the  same 
plan  in  the  common  viper  (Pelias  berus),  not  uncom- 
mon in  Central  and  Southern  Europe,  and  easily  re- 
cognised by  its  dark  green  colour,  and  by  the  zigzag 
black  line  in  the  middle  of  the  back.  Other  poisonous 
snakes  like  the  asp,  the  cobra  di  capello,  and  the  coral 
snake,  have  other  solid  teeth  coexisting  with  the  poi- 
son fangs,  and  some,  like  the  dipsads,  tree  snakes,  and 
sand  snakes,  have  some  of  the  hinder  teeth  grooved. 
The  poison  of  snake-bites  is  rapidly  fatal,  death 
taking  place  within  an  hour  in  general,  and  it  is  com- 
puted that  over  10,000  deaths  take  place  annually 
from  this  cause  among  human  beings. 

The  water  snakes  inhabit  the  Pacific  and  Indian 
Ocean,  and  have  flat  tails.  They  possess  strong  un- 
grooved  teeth  behind  the  true  poison  fangs.  In  one 
species,  allied  to  the  coral  snake  ( Callophis  inttstinalis), 
the  poison  gland  extends  into  the  abdomen. 

One  curious  group  of  non-poisonous  snakes  pos- 
sess teeth  on  the  anterior  surface  of  the  neck  vertebrae 
in  addition  to  feeble  jaw  teeth.  These  animals  feed 
on  eggs,  and  use  these  teeth  for  breaking  them  while 


Tortoises.  49 

in  the  act  of  swallowing,  so  that  all  the  material  of 
the  egg  may  be  saved  for  food.  Snakes  are  rare  in 
cold  and  more  abundant  in  warm  climates ;  they  are 
also  more  numerous  in  continental  than  in  insular 
regions. 


CHAPTER   X. 

TORTOISES   AND   CROCODILES. 

27.  Order  3,  Chelonia  (Tortoises). — This  order 
consists  of  those  reptiles  whose  bodies  are  enclosed 
in  a  bony  case  composed  of  a  dorsal  or  upper  convex 
shield,  called  the  carapace  and  a  flat  ventral  or  under 
shield,  the  plastron.  The  carapace  is  notched  in 
front  and  behind,  and  between  it  and  the  plastron 
project  the  head  and  neck,  the  limbs,  and  the  tail. 
These  parts  can  be  retracted  under  cover  of  the  bony 
case.  Each  shield  consists  of  a  layer  of  epidermis  or 
tortoise-shell,  and  a  layer  of  bone,  which  in  the  cara- 
pace consists  of  dermal  plates  added  to  the  tops  of 
the  spines  of  the  vertebrae,  the  surfaces  of  the  ribb; 
and  a  row  of  marginal  bony  plates  below  these.  The 
plastron  also  consists  of  nine  plates  of  ossified  dermis 
covered  by  a  symmetrical  series  of  horny  laminae. 
The  skull  is  short,  rounded,  and  not  armed  with 
teeth,  which  are  replaced  by  horny  beak-like  jaws. 
The  lower  jaw  is  in  one  piece  in  the  adult.  The 
shoulder-girdle  consists  of  three  bony  rods,  two  in 

E 


50  Vcrtebrata. 

front,  and  one  behind  ;  these  are  included  within  the 
carapace,  as  also  is  the  pelvic  girdle. 


FIG.  21. 


Skeleton  ol  European  tortoise,  the  plastron  or  under-shell  removed. 


Crocodiles.  5 1 

The  land  forms  included  under  this  order  are 
tortoises,  such  as  the  common  Greek  tortoise,  which 
live  on  land  and  have  stumpy  feet  with  short  nails. 
The  aquatic  forms  or  turtles,  such  as  the  green  turtle 
used  in  making  turtle  soup,  and  the  hawks- bill  turtle 
used  for  its  '  tortoise  shell,'  are  known  by  their  webbed 
feet.  The  largest  tortoises  of  the  present  day  only 
measure  a  few  feet  in  length,  but  in  ancient  days 
tortoises  reached  enormous  sizes ;  thus  the  Colosso- 
chelys,  or  ,giant  fossil  tortoise  of  India,  sometimes 
reached  a  length  of  over  thirteen  feet.  Tortoises  are 
slow  in  growth,  and  attain  to  extraordinary  ages. 
They  are  for  the  most  part  vegetable  feeders,  differ- 
ing in  this  respect  from  most  other  reptiles. 

28.  Order  4,  Crocodilia.—  These,  the  highest  in 
organisation  of  the  entire  class,  are  inhabitants  of  the 
rivers  of  tropical  countries,  and  are  among  the  largest 
of  living  reptiles.  Tvey  have  a  rough,  hard,  scaly 
coat  of  epidermis  which  is  placed  dorsally  on  a 
dermal  bony  surface.  The  vertebral  column  is  pro- 
vided with  ribs,  and  is  composed  of  vertebrae  hollow 
in  front  and  convex  behind.  The  skull  is  long,  and 
covered  with  peculiar  sculptured  markings.  The  teeth 
are  seated  in  sockets  in  one  row,  and  are  renewed 
several  times  in  succession.  The  heart  has  a  com- 
plete septum  or  partition  in  the  ventricle  dividing  it 
into  two  distinct  cavities,  but  the  aortic  arches  still 
communicate  with  each  other  at  their  base?.  The 
feet  are  webbed  and  possess  strong  claws,  and  there 
are  dermal  glands  in  the  throat  secreting  a  peculiar 
musky  material.  The  forms  included  are  the  croco- 
diles of  the  Nile  and  Indian  rivers,  with  their  long 

E2 


52  Vertebrata. 

tapering  snouts,  in  which  the  longest  teeth  of  the  lower 
jaw  notch  the  sides  of  the  upper  jaw.  The  alligators 
of  the  New  World  have  heads  oval  or  rounded  in 
front,  and  in  all  of  them  the  lower  jaw  teeth  are 
hidden  by  the  edge  of  the  upper,  when  the  mouth  is 
closed.  The  gavial  of  the  Ganges  has  a  long,  slender- 
pointed  head,  and  is  the  smallest  of  the  group. 

Of  all  the  reptiles  the  crocodiles  are  those  which 
in  point  of  structure  approach  most  closely  to  the 
birds.  They  have  a  gizzard-like  stomach,  a  nictitat- 
ing membrane  in  the  eye,  an  immovable  joint  between 
the  tibia  or  leg  bone  and  the  first  bone  of  the  tarsus 
or  ankle,  a  single  carotid  or  neck-artery,  and  many 
other  structural  peculiarities  which  show  their  super- 
iority over  other  reptiles.  Among  the  orders  of  the 
reptile  class  now  extinct,  there  was  one  which  in- 
cluded bipedal  forms  which  had  possibly  a  kangaroo- 
like  mode  of  progression,  and  one  of  flying  reptiles, 
which  indicated  a  still  closer  relationship  to  the  birds. 


CHAPTER  XL 

CLASS  IV. — AVES  (BIRDS). 

29.  General  Characters. — These  familiar  verte- 
brates are  characterised  by  possessing  an  epidermal 
clothing  of  feathers,  warm  blood,  a  four-chambered 
heart,  no  teeth,  and  in  general  an  adaptation  for  aerial 
locomotion.  The  mode  of  progression  on  the  earth 


Feathers. 


53, 


V 


is  strictly  bipedal,  as  the  fore-limbs  never  touch  the 
ground,  being  modified  into  wings.    Like  reptiles  they 
are  oviparous  and  their  eggs 
are  of  large  size  ;  in  most  cases 
also  the  young  are  for  a  certain 
period  under  the  care  of  the 
mother,  by  whose  agency  they 
are  provided  with  food. 

30.  Feathers,  —  Feathers 
are  epidermal  processes  se- 
creted by  long  grooved  papillse* 
and  they  are  of  several  sorts. 
The  strong  distinct  feathers, 
which  have  a  central  axis  and 
lateral  expansions  or  vanes,  are 
called  contour- feathers,  while 
the  smaller  soft  feathers  which 
clothe  the  intimate  surface  of 
the  skin,  which  have  soft  or 
woolly  processes  and  no  axis, 
are  called  down-feathers.  In 
each  contour-feather  we  notice? 
firstly,  the  hole  at  the  base  (fig. 
22,  e)  where  it  is  thickened 
around  the  base  of  the  papilla ; 
secondly,  the  slit-like  hole,  /, 
marking  the  region  above  which 
the  sheath  of  the  papilla  has 
split ;  thirdly,  the  rachis,  or  the 
square  solid  axis,  b  ;  fourthly, 

the    flat    expanded    lamina,    Or    a,  barrel ;  b,  rachis  ;  c,  vanes  ; 
j       c  /".  upper  umbilicus  and  after- 

Vaiie,  C)  composed  of  separate       shaft;  c,  \ 

barbs,  the  margins  of  each  of 


Contour-feather. 


,  lower  umbilicus. 


54  Vertebrata. 

which  are  joined  to  their  neighbours  by  numerous 
hooklets. 

In  this  respect  contour-feathers  differ  from  down, 
in  which  the  barbs  are  all  discontinuous.  In  young 
birds  the  entire  plumage  consists  of  simple  down- 
feathers  covering  the  whole  surface  almost  uniformly, 
and  in  some  birds  which  do  not  possess  the  power  of 
flight,  this  condition  is  more  or  less  perpetuated,  and 
thus  all  the  feathers  have  discontinuous  barbs,  as  in 
the  ostriches.  In  the  great  majority  of  birds,  how- 
ever, this  primitive  surface  clothing  is  shed  and  be- 
comes replaced  by  a  second  growth  of  feathers,  which 
differs  from  the  first  in  that  the  component  feathers 
are  for  the  most  part  contour- feathers,  arranged  in 
definite  tracts,  and  between  these  pteryla,  or  feather 
tracts,  there  are  spaces  quite  devoid  of  contour-feathers. 
In  the  course  of  life,  many  birds  change  their  feathers 
several  times,  the  process  being  called  '  moulting.' 
To  defend  the  feathers  from  the  influence  of  moisture 
there  is  a  gland  situated  on  each  side  of  the  tail  bone 
which  secretes  an  oily  material  of  use  in  lubricating 
the  plumage.  The  largest  feathers  are  those  of  the 
wing,  and  they  are  grouped  into  primaries,  secondaries, 
and  tertiaries,  according  as  they  are  borne  respectively 
by  the  hand,  the  lower,  or  the  upper  end  of  the  fore- 
arm ;  over  these  are  the  scapulars,  and  on  the  rudi- 
mental  thumb  is  the  alula.  The  tail  feathers  are 
also  long,  and  as  they  are  used  in  steering  they  are 
named  rectrices  to  distinguish  them  from  the  oar- 
feathers  of  the  wing. 

The  papillae  which  secrete  the  feathers  are  long, 
vascular,  and  deeply  grooved  on  the  surface ;  the 


Plumage  and  Skeleton  of  Birds.  5  5 

protoplasmic  matter  exuded  by  the  surface  of  the 
papillae  is  collected  into  these  channels,  it  then  hardens 
and  forms  in  the  first  place  a  hollow  cylinder  of  horny 
matter,  with  ridges  fitting  into  the  papillary  grooves 
and  thin  areas  between.  As  growth  takes  place  most 
actively  at  the  base  of  the  papilla,  this  horny  sheath 
is  pushed  off  the  surface  of  the  papilla,  upon  which  it 
shrinks  still  more,  and  the  horny  cylinder  splits  along 
its  thinnest  side,  whereupon  the  two  lateral  laminae 
flatten  out  as  the  vanes,  while  the  rib  which  corre- 
sponded to  the  main  groove  of  the  papilla  becomes 
the  rachis.  The  feathers  of  many  birds  are  of  brilliant 
colours,  usually  brighter  in  the  males  than  in  the 
females. 

31.  Bones. — The  skeleton  of  birds  is  well  adapted 
for  their  aerial  existence.  The  skull  is  early  consoli- 
dated, and  articulates  with  the  spine  by  one  occipital 
condyle.  The  ten  or  twelve  parts  of  the  lower  jaw 
are  also  early  united  into  a  single  piece  and  the  front 
of  the  jaw  is  enclosed  in  a  horny  sheath ;  it  articulates 
to  the  skull  by  means  of  a  movable  quadrate  bone 
which  is  kept  in  its  place  by  two  rods  of  bone,  one 
on  the  outside  stretching  from  the  base  of  the  upper 
beak  (the  jugal  arch),  the  other  on  the  inside  stretch- 
ing from  the  palate  (the  pterygoid  arch).  The  upper 
mandible,  or  beak,  is  also  encased  in  a  horny  layer 
at  whose  base  are  the  nostrils,  very  often  surrounded 
by  a  thick  leathery  skin,  which  is  called  the  cere. 

The  neck  is  usually  long  and  exceedingly  flexible, 
made  up  of  from  nine  to  twenty-three  vertebrae  ;  its 
length  and  that  of  the  bill  usually  bears  some  propor- 
tion to  the  length  of  the  legs.  The  breast-bone  bears 


56  Vertebrata. 

in  front  a  prominent  keel,  to  which  the  muscles  which 
elevate  and  depress  the  wing  are  attached,  and  this  is 
only  absent  in  such  birds  as  do  not  fly,  as  the  ostrich, 
emu,  and  New  Zealand  ground  parrot.  The  wings 
are  fastened  to  a  very  strong  shoulder-girdle,  which 
consists  of  three  parts  ;  firstly,  of  a  v- shaped  furculum, 
or  merrythought,  which  consists  of  the  two  collar- 
bones united  together  in  the  middle  line  \  secondly, 
FIG.  23.  of  the  coracoid  bone,  a  stout 

bony  rod  which  fits  into  a 
groove  in  the  top  of  the 
breast-bone  and  stretches 
from  thence  upwards  and 
backwards  to  the  shoulder 
joint ;  thirdly,  the  scapula,  or 
scythe-blade-like  bone,  which 
joints  with  the  coracoid  at 
the  shoulder,  and  descends 
backwards  over  the  dorsal 
ribs,  slung  in  its  place  by 
muscles.  The  wing  bones 
consist  of,  firstly,  an  arm 
bone,  or  humerus ;  secondly, 
Pelvis  of  bird.  two  forearm  bones  ;  thirdly, 

a,  sacrum;    b,  lumbar  vertebrae;  ..  ,          , 

d,  ilium ;  /,  pubis ;  g,  sciatic  a  consoliaatecl   hand   made 

foramen ;  k,  ischium.  /•  i     / 

up  of  several  (never   more 

than  four)  united  fingers,  of  which  only  the  thumb  in 
general  bears  a  claw,  rarely  the  thumb  and  index 
fingers,  as  in  the  cassowary.  The  ribs  are  few  and 
are  fastened  together  by  lateral  spurs,  or  processes. 
The  portions  of  the  ribs  which  articulate  with  the 
vertebral  column  are  separate  from  those  that  unite 
with  the  breast  bone. 


Feet  of  Birds.  57 

The  tail  bones  are  short  and  compressed,  forming 
a  ploughshare-like  process  ;  the  pelvic  bones  are  long, 
and  stretch  along  the  spine  fore  and  aft  to  an  extent 
proportionally  unmatched  in  the  rest  of  the  sub-king- 
dom (fig.  23).     The  two  pubic  bones  do  not  unite  in 
the  middle  line  in  front  of  the  pelvis  except  in  the 
ostrich,  but  always  remain  separate  and  open.     The 
thigh  bones  are  short.     The  leg-bone  consists  of  two 
arts,  which  in  adult  birds  are  indistinguishably  united, 
these  the  largest   part   is  the   tibia,  or  leg-bone 
proper,  the  lower  end  consists  of  the  astragalus,  or 
st  bone  of  the  tarsus  or  ankle.     The  lower  part  of 
tie  shank  of  a  bird  consists  of  the  remaining  tarsal 
and  metatarsal  bones  elongated  into  a  single  shaft, 
and  below  this  are  the  toes,  of  which  usually  four  are 
developed.     The  innermost  of  these  or  the  hind  toe 
onsists  in  general  of  two  joints  or  phalanges,  the 
econd  (inner)  toe  is  made  up  of  three,  the  middle 
or  longest  toe,  of  four,  arid  the  outermost  toe  of  five 
phalanges.     The  shapes  and  dispositions  of  the  toes 
p  with  the  habits  of  the  birds  ;  thus,  birds  of  prey 
ave  stout,  grasping  feet,  with  sharply  hooked  claws. 
Climbers,  like   woodpeckers   and   parrots,   have  the 
outer  and  inner  toes  turned  backwards  and  the  other 
vo  forwards.     In  swimmers,  all  the  forward  toes  are 
vebbed,   while  in  the   scraping  birds   the   toes  are 
tiort,  stout,  and  armed  with  blunt  nails.     Many  of 
he  bones  in  the  body  of  a  bird  are  hollow,  and  in- 
itead  of  containing  marrow  they  are  lined  by  a  deli- 
ate  membrane  and  contain  air,  which  is  conducted 
nto  them  from  the  respiratory  organs  by  thin  walled 
canals.     This  condition  is  specially  exhibited  in  the 


58  Vertebrata. 

birds  of  most  powerful  flight,  but  the  bones  of  very 
young  birds  contain  marrow. 

32.  Muscles  and  Viscera. — The  muscle  or  flesh 
of  birds  consists  of  very  close  fibres,  and  the  sinews 
or  tendons  are  often  converted  into  bone.  There  is 
an  enormous  muscle  on  the  front  of  the  breast,  the 
great  pectoral,  whose  action  is  to  depress  the  wing ; 
beneath  this  is  a  smaller,  or  second  pectoral  muscle 
with  oblique  fibres,  arranged  like  the  barbs  of  a  feather, 
and  converging  to  a  tendon  which,  winding  round  a 
pulley  at  the  top  of  the  coracoid,  is  inserted  into  the 
top  of  the  humerus  and  raises  the  wing ;  this  is  the 
second  pectoral.  In  the  legs  of  many  birds  there  is 
to  be  found  superficially  on  the  front  of  the  thigh  a 
slender  little  muscle,  which,  starting  from  the  front  of 
the  pelvis,  passes  down  the  upper  or  front  surface  of 
the  thigh,  winds  round  to  the  back  of  the  knee  and 
runs  by  a  tendon  into  the  superficial  flexor  (or  bender) 
muscle,  for  the  longest  toe  (plantaris)  ;  a  second 
muscle  (the  peroneus),  from  the  outside  of  the  leg  can 
generally  be  traced  into  the  same  toe-muscle.  These 
muscles  are  supposed  to  be  of  importance  in  the 
action  of  perching,  and  as  their  tendons  pass  over 
several  joints  they  probably  have  a  complex  action. 

The  digestive  system  of  birds  consists  of  the  fol- 
lowing parts  :  first,  the  bill  or  prehensile  organ,  vary- 
ing in  shape  and  texture  according  to  the  nature  of, 
and  mode  of  obtaining,  the  food  upon  which  the  bird 
subsists  ;  secondly,  the  tongue,  rarely  soft,  usually 
hard  and  horny,  often  barbed  ;  thirdly,  the  long  food- 
passage,  or  oesophagus,  which,  above  the  furculum, 
usually  dilates  into  a  crop  (fig.  24,  £),  below  which  is 


Viscera  of  Birds. 


59 


a  glandular  stomach  (c)  communicating  with  the 
gizzard,  or  true  muscular  stomach  »V).  This  cavity 
has  a  thick  muscular  wall  consisting  chiefly  of  two 
masses  of  muscle  united  by  a  strong  tendon,  and 
lined  by  a  rough  horny  cuticle  ;  into  this  birds  fre- 
quently introduce  small  stones  which  assist  in  tri- 
turating or  grinding  the  food,  as  this  organ  is  chiefly 
the  place  where  the  material  of  the  food  is  reduced 

FIG.  24. 


b,  crop  :  c,  c,  glandular  stomach  and  gizzard. 

mechanically  to  a  condition  of  pulp  to  prepare  it  for 
further  digestive  changes.  The  gastric  juice  secreted  in 
the  glandular  stomach  is  here  thoroughly  mixed  up 
with  it,  and  the  food  mass  is  thus  prepared  for  the 
intestinal  canal.  The  gizzard  is  especially  strong  in 
grain,  or  fruit-eaters,  weak  or  absent  in  flesh-eaters. 

Birds  have  two  separate  ventricles  in  the  strong 
muscular  heart ;  one  on  the  right  side  for  propelling 


6o 


Vertebrata. 


the  impure  or  venous  blood  of  the  right  auricle  into 
the  lungs,  and  the  other,  or  left  ventricle,  for  driving 
the  purified  blood  after  its  return  from  the  lungs, 
through  the  body ;  the  opening  into  the  right  ventri- 
cular cavity  from  the  auricle  is  guarded  by  a  muscular 
flap.  There  is  only  one  aortic  arch  developed  in  the 
adult  bird,  and  it  arches  to  the  right  side,  and  in  many 
birds  there  is  only  one  artery  developed  in  the  neck 
for  the  supply  of  the  head.  The  lungs  are  large,  and 
surrounded  on  their  lower  surfaces  by  large  air-sacs, 
into  which  the  bronchial  tubes  distinctly  open ;  from 
these  cavities  pass  the  membranous  canals,  which 
convey  the  air  to  the  principal  bones.  There  is  no 
muscular  layer  underlying  the  lungs  for  the  purpose 


FIG.  25. 


Organ  of  voice  of  the  raven. 
A,  front  view  ;  B,  side  view  showing  the  muscles  of  vocalisation. 

of  directly  acting  on  them  in  respiration,  except  in  the 
ostrich  and  apteryx  ;  but  as  the  sternal  and  vertebral 


Voice  and  Senses  of  Birds.  6 1 

ribs  can  move  on  each  other,  the  bony  wall  of  the 
thorax  or  chest  cavity  is  susceptible  of  a  large  range  of 
motion  for  breathing. 

As,  from  the  activity  of  their  motion,  birds  require 
a  more  perfect  system  of  nutrition  for  their  ultimate 
tissues  and  organs  than  reptiles,  their  respiratory 
apparatus  is  very  highly  developed,  and  hence  their 
temperature  is  higher  than  that  of  any  other  group  of 
animals.  9 

An  organ  of  voice  is  usually  developed  in  the 
air-passages  of  birds,  most  commonly  at  the  point 
where  the  windpipe  or  trachea  bifurcates  to  send  an 
air-tube  to  each  lung  (fig.  25).  At  this  spot  there  is 
a  drum-like  cavity  or  syrinx  (g),  in  which  certain  tense 
membranes  can  be  made  to  vibrate,  and  can  be  acted 
on  by  muscles  (a,  ft,  c,  d,  e\  attached  to  the  windpipe. 
Thus  the  organ  differs  from  that  in  mammals,  in 
which  the  seat  of  voice  is  the  larynx  or  upper  end 
of  the  windpipe.  In  the  wild  swan  the  long  and 
sinuous  windpipe  is  contained  in  a  hollow  which  is 
provided  for  its  reception  in  the  keel  of  the  sternum. 

The  blood  of  birds  contains  small  elliptical  cor- 
puscles which  are  nucleated. 

The  eye  of  birds  is  remarkable  for  possessing 
bony  plates  in  its  '  white/  as  well  as  a  curious  folded 
vascular  projection  at  the  bottom  of  the  eyeball,  which 
projects  forwards  towards  the  crystalline  lens.  There 
is  also  a  third  eyelid,  or  nictitating  membran^,  placed 
below  and  within  the  two  ordinary  lids,  and  moved  by 
two  little  muscles  on  the  back  of  the  eyeball,  and 
there  is  an  additional  gland  whose  secretion  keeps 
this  accessory  lid  moist.  The  senses  of  smell  and 


62  Vertebrata. 

hearing  are  also  largely  developed  in  some  birds, 
notably  in  vultures  and  owls,  the  latter  being  pro- 
vided with  a  distinct  external  ear. 

Most  birds  have  but  one  oviduct,  and  that  is  on 
the  left  side  ;  in  its  lining  there  are  glands  which 
secrete  the  white  of  the  egg,  its  membrane,  and  the 
shell,  during  the  downward  passage  of  the  yolk.  The 
embryonic  bird  is  provided  with  a  rudimental  knob 
on  its  pre-maxillary  bones,  which  it  uses  in  breaking 
the  egg-shell  wherein  it  is  contained. 


CHAPTER  XII. 

CLASSIFICATION   OF   BIRDS. 

33.  Primary  Divisions. — About  8,000  species  01 
birds  are  known  to  the  naturalist,  and  these  are  divided 
into  two  primary  sub-classes. 

The  first  sub-class  is  called  Ratidce,  and  includes 
all  those  birds  which  have  a  sternum  without  a  keel,  a 
rudimentary  furculum  and  wings,  feathers  with  discon- 
tinuous barbs  and  not  distributed  in  feather  tracts, 
and  with  no  oil  gland.  They  are  all  natives  of  warm 
or  temperate  climates,  and  strictly  limited  in  their 
range.  Several  gigantic  forms  which  existed  until 
recently,  are  now  extinct,  such  as  the  moa  of  New 
Zealand  and  the  sepyornis  of  Madagascar.  The 
ostrich  of  Africa  is  a  familiar  instance,  and  is  pro- 
vided only  with  two  toes.  The  American  ostrich 
or  rhea  is  smaller,  and  inhabits  South  America. 


Parrots  and  Cuckoos.  63 

The  cassowary  is  a  native  of  the  East  Indian  archi- 
pelago, and  the  emu  of  the  Australian  continent. 
The  apteryx  of  New  Zealand  is  the  most  remarkable 
of  these  birds,  as  it  has  perfectly  rudimentary  wings 
and  a  long  slender  bill,  and  there  is  a  remarkable 
disproportion  between  the  size  of  the  egg,  which  is 
very  large,  and  that  of  the  bird. 

The  second  sub-class  of  birds  is  called  Carinat<z 
and  includes  all  those  birds  which  have  a  keel  on  the 
breast -bone,  -a  merrythought,  usually  functional 
wings,  whose  feathers  are  in  tracts  (except  in  the 
penguins)  and  have  the  barbs  united  along  their 
margins.  This  includes  fourteen  orders  of  birds,  of 
many  of  which  there  are  familiar  illustrations  easily 
obtainable. 

34.  Order  1,  Parrots  (Psittaci). — The  most  in- 
telligent and  most  highly  organised  of  birds ;  easily 
known  by  their  sharply  FIG.  26. 

hooked  beaks,  both  the 
upper  and  lower  part  of 
which  are  movable,  and 
by  their  brightly-coloured 
feathers.  Their  feet  are 
prehensile,  the  outer  and 
inner  toes  being  turned 

backwards,  While    the  tWO    n  nostril ;  e,  quadrate  bone  ;  v.  lower 

middle    toes  are    turned  jaw '  m' orbit 

forwards,  and  thus  they  are  enabled  to  grasp  in  climb- 
ing. The  tongue  is  soft,  and  the  muscles  which  move 
it  are  more  distinct  than  those  of  most  birds,  and 
hence  the  singular  power  of  mimicking  sounds  pos- 
sessed by  many  of  them.  They  are  natives  of  the 


64  Vertebrata. 

tropics,  the  cockatoos  being  mostly  from  the  East 
Indian  archipelago,  the  macaws  from  South  America, 
the  common  parrots  from  Africa  and  Madagascar. 
One  curious  genus,  Strigops,  the  ground  parrot  of 
New  Zealand,  is  exceptional  in  having  no  keel  on  its 
sternum,  and  some  parakeets  from  Australia  have  no 
merrythought.  They  are  vegetable-feeders,  princi- 
pally subsisting  on  fruits,  but  often  eating  honey. 
Many  species  live  long  in  confinement,  and  they  are 
all  easily  domesticated. 

35.  Order  2,  Cuckoos,  &c.  (Coccygomorphae). — 
These  are  usually  long-beaked  birds  with  small  flat 
tongues,  having  the  toes  arranged  either  permanently 
or  temporarily  like  those  of  parrots,  with  the  outer 
and  inner  turned  backwards.     The  wings  have  long 
covering  feathers.     Some  of  these  birds  have  enor- 
mous beaks  thrice  as  long  as  the  head,  like  the  little 
toucans  of  America ;   in   others   the  beaks  are  sur- 
mounted  with   great  horns,   made  of  spongy  bony 
tissue  covered  with  horn,  as  in  the  hornbills  of  the 
Eastern  tropics.     Other  examples  of  this  order  are 
the  cuckoos,  so  familiar  for  their  peculiar  note  and  for 
their  habit  of  laying  eggs  in  the  nests  of  other  birds  ; 
the  kingfishers,  bee-eaters,  hoopoe,  rollers,  &c.    Some 
are   remarkable   for  their  colours,  like  the  plantain- 
eaters  of  Africa.    The  tongues  are  hard,  often  bristled, 
as  in  the  toucans;  few  have  much  vocal  power.     They 
are  for  the  most  part  feeders  on  insects  and  animal 
substances. 

36.  Order    3,    Woodpeckers     (Pici).  —  Mostly 
brightly-coloured  birds,  with  straight,  strong,  conical 
beaks,  and  slender  and  actively  protrusible  tongues. 


Swifts  and  Humming  Birds. 


Frc.  27. 


The  wings  have  short  coverts.  The  middle  toes  are 
united  at  the  base ;  the  inner  toe  is  small,  directed 
backwards,  as  is  also  the  outer 
toe.  The  tail  feathers  are  short, 
stiff,  and  serve  as  organs  of 
support.  These  are  insect-eat- 
ing birds  like  the  last  group, 
and  they  derive  their  name  from 
their  efforts  after  the  capture 
of  their  prey.  In  these  the 
tongue  bone  is  specially  elon- 
gated, and  its  lateral  processes 
coiled  and  disposed  to  allow 
of  the  rapid  protrusion  of  the 
barbed  tongue.  Woodpeckers  of  woodpecker, 

exist  everywhere  but  in  Madagascar  and  Australia. 

37.  Order  4,  Swifts  and  Humming-Birds  (Macro- 
chires). — A  small  order  of  birds,  mostly  of  very 
minute  size,  and  almost  all  of  powerful  flight.  Some 
of  these,  like  the  swifts,  have  flattish  beaks;  others, 
like  the  humming-birds,  have  long  tubular  bills.  In 
each  wing  the  forearm  and  hand  greatly  exceed  in 
length  the  upper  arm,  hence  the  Latin  name  given  to 
the  order.  The  feet  are  very  weak,  scarcely  able  to 
support  the  weight  of  the  body,  and  the  inner  toe 
may  in  some  be  turned  forwards  or  backwards.  They 
have  a  very  simple  syrinx,  and  little  or  no  voice. 
They  are  mostly  tropical  birds,  and  vary  much  in 
size,  the  goatsuckers  being  the  largest,  sometimes  of 
comparatively  large  size  ;  while  the  swifts  are  much 
smaller  and  somewhat  swallow-like.  One  of  these, 
the  Collocalia  of  the  Malay  archipelago,  secretes,  by 


66  Vertebrata. 

means  of  glands  in  the  throat,  a  glutinous  material  of 
which  it  constructs  its  nests,  which  are  the  edible 
birds'  nests  of  Eastern  commerce,  used  as  food  in 
China.  The  humming-birds  of  Brazil,  of  which  there 
are  very  numerous  species,  are  also  examples  of  this 
order,  and  include  the  smallest  forms  of  the  entire 
class  of  birds;  thus  Melisuga  minimus,  from  the  island 
of  San  Domingo,  only  weighs  about  nine  grains,  and 
measures  two  inches  in  extreme  length  ;  its  nest  is 
about  the  size  of  a  walnut,  and  it  contains  two  eggs 
each  nearly  as  large  as  a  pea. 

38.  Order  5,  Perching  birds  (^asseres.) — This 
large  order  includes  all  our  small  birds,  with  the  ex- 
ception of  those  hitherto  mentioned.     They  may  be 
recognised  by  possessing  short  wing  coverts,  a  tarsus 
FIG.  28.  covered  in  front  with  seven  large 

scales,  and  slender  toes,  of  which 
the  first  joints  of  the  two  outer  are 
united.  They  have  a  well-deve- 
loped syrinx  or  organ  of  voice,  and 
many  of  them  can  sing.  These  birds 
are  very  numerous,  and  make  up 

Foot  of  passerine  bird.        •,  -        .,. 

about  twenty-one  families.  The 
best  known  of  these  are  the  following  : — The  thrushes, 
known  by  their  slightly  curved  bill,  with  a  notch  or 
tooth  on  each  side  near  the  tip,  and  with  bristles  at 
the  angles  of  the  gape  of  the  mouth.  They  are 
insect-eaters  for  the  most  part.  The  commonest 
species  are  the  song  thrush;  the  blackbird,  known 
by  its  yellow  bill  and  eyelid-edge  and  its  black 
body ;  the  missel  thrush,  known  by  its  white-tipped 
three  outer  tail  feathers  ;  the  fieldfare,  the  redwing. 


Passerine  Birds.  67 

To  this  family  belongs  the  mocking  bird  of  America, 
which  can  mimic  the  song  of  any  other  bird.  The 
birds  of  the  wagtail  family  are  recognisable  by  their 
slender  forms,  long  legs,  long  tails,  and  moderate 
wings  with  nine  primary  feathers.  They  include  the 
common  pied  wagtails,  the  yellow-breasted  wagtail ; 
closely  allied  to  which  are  the  hedge-sparrows  (Ac- 
centor) with  strong,  sub-conical,  straight  bills,  and 
wings  with  a  very  short  first  quill,  the  third  and  fourth 
primaries  being  the  longest.  The  warbler  family, 
consisting  of  small  singing  birds  with  awl-shaped 
beaks  flattened  at  base,  are  also  closely  allied ;  of 
these  the  most  familiar  examples  are  the  nightingales 
(Philomela)  \  robin  red-breasts  of  Europe  ;  red-starts 
(Phanicura)  ;  sedge  and  grasshopper  warblers  (Sal- 
icaria)  ;  white-throats,  black-caps  (Curruca) ;  and 
willow-wrens  (Sylvia).  The  gold-crested  kinglet 
(Regulus)  is  the  smallest  American  bird  of  this  order, 
its  length  being  under  4  inches.  The  pipits  (Anthus), 
have  awl-shaped  bills,  keeled  at  the  base  above,  with 
two  long  scapular  feathers  and  long  hind  claw.  In 
North  America  the  warblers  (SilviidcB)  of  Europe  are 
represented  by  the  Silvicolida  or  American  warblers. 
The  crow  family  (Corvida)  constitute  a  group  of 
much  larger  birds  ;  they  have  strong  conical  bills  with 
no  notch,  and  robust  feet.  This  family  includes  the 
jackdaw,  crow,  raven,  jay,  and  magpie,  and  the  star- 
ling is  a  nearly  related  form.  These  have  ten  pri- 
mary feathers,  while  the  birds  of  the  conical-billed 
finch  family  possess  only  nine.  This  family  consists 
of  the  house-sparrows,  hawfinches,  linnets,  bullfinches, 
and  nearly  related  are  the  larks  and  buntings. 


68  Vertebrate. 

Among  the  most  remarkable  tropical  forms  are 
the  lyre-birds  of  Australia,  the  oven-builders  of  Brazil ; 
the  sun-birds,  nuthatch,  wax-wings,  &c. 

39.  Order  6,  Birds  of  Prey  (Raptores). — This 
order  consists  of  eagles,  owls  and  vultures,  which 
feed  on  animal  food,  and  are  armed  with  strongly 
hooked  bills  (fig.  30),  and  with  strong,  sharp  and 
curved  claws  (fig.  29).  At  the  base  of  the  bill  is  a 

Fig.  29.  FIG.  30 


Foot  of  eagle.  Head  of  eagle. 

cere  or  skin,  which  is  pierced  by  the  nostrils.  The 
gizzard  is  weak,  the  digestive  tract  short,  the  sense 
organs  are  acute  and  powerful.  Their  strong  wings 
have  ten  primary  feathers,  and  the  tail  has  twelve 
rectrices.  Owls  are  mostly  nocturnal,  round-faced 
birds,  with  short  beaks,  and  with  eyes  directed  for- 
wards. They  have  no  crop,  and  peculiarly  soft  plu- 
mage. Some  have  tufts  of  feathers  above  the  ears, 
such  as  the  horned  owls.  Vultures  are  carrion -eaters, 
most  abundant  in  warm  climates,  with  naked  or  down- 
clad  head  and  longer  bills.  Eagles  have  feather- 
clad  heads,  and  short,  sharply-hooked  bills,  and  they 
for  the  most  part  feed  on  prey  which  they  kill  for 


Pigeons  and  Poultry.  69 

themselves.  To  this  family  belong  the  hawks,  kites, 
buzzards  and  harriers,  as  well  as  the  larger  eagles, 
ospreys,  and  falcons. 


CHAPTER  XIII. 

CLASSIFICATION   OF   BIRDS    CONTINUED. 

40.  Order  7,  Pigeons  (Gyrantes). — This  well- 
marked  group  consists  of  the  doves  and  pigeons, 
characterised  by  having  a  gristly  plate  covering  the 
base  of  the  upper  mandible,  pierced  in  front  by  the 
nostrils.  They  are  vegetable-feeders,  with  a  large 
glandular  crop  which  sometimes  secretes  a  milky  fluid 
with  which  the  parents  nourish  the  young  birds. 
They  have  a  strong  gizzard,  shielded  or  feathered 
tarsi,  and  four  usually  free  toes  all  on  the  same  level, 
with  short,  slightly-hooked  claws.  They  are  mostly 
birds  of  powerful  flight,  and  have  ten  primary  quill 
feathers  in  their  long  pointed  wings,  and  twelve  or 
rarely  sixteen  rectrices.  They  are  mostly  social  birds, 
often  living  in  great  societies.  The  pigeons,  wood- 
quests,  and  doves  are  familiar  instances,  as  also  are 
the  passenger  pigeons  of  North  America,  which  mi- 
grate in  millions,  darkening  the  air  by  their  flocks. 
Our  common  pigeons,  in  all  their  varieties,  are  de- 
scended from  the  rock-dove,  Columba  livia.  The 
curious  dodo  of  Mauritius  was  an  aberrant  large 
pigeon  incapable  of  flight,  and  hence  it  was  easily 


70  Vertebrata. 

captured  by  the  early  voyagers,   and  was  extirpated 
in  the  seventeenth  century. 

41.  Order  8,   Scraping    birds    (Rasores).—  This 
large  and  economically  important  order  includes  the 

FIG.  31.  poultry,      turkeys,      pheasants, 

grouse,  partridge,  &c.,  heavy 
plump-bodied  birds,  with  com- 
paratively small  rounded  wings, 
weak  in  flight,  and  with  a  mode- 
rate length  of  beak  and  legs; 
they  have  stout  blunt  claws,  the 
hind  toe  being  raised  above  the 
level  of  the  others.  The  name  of  the  order  is  derived 
from  the  habit  common  to  most  of  them  of  scraping 
in  searching  for  their  food  in  or  on  the  ground.  The 
tarsus  often  bears  spurs,  especially  in  the  males,  and 
the  plumage  is  close  and  often  brilliantly  coloured,  as 
in  the  peacocks  and  pheasants.  Many  of  them  have 
naked  areas  on  the  head,  where  the  skin  is  soft 
and  vascular,  forming  wattles  or  crests.  As  they  are 
mostly  grain-eaters,  they  have  large  muscular  gizzards, 
capacious  crops,  and  long  intestines.  Our  common 
domestic  fowls  are  natives  of  India,  as  also  is  the 
peacock  and  that  most  gorgeously  coloured  bird  the 
Impeyan  pheasant,  whose  plumage  has  a  rich  metallic 
lustre.  The  golden  pheasant  is  a  native  of  China,  the 
turkey  of  America.  In  Australia  the  order  is  repre- 
sented by  the  mound-birds  and  brush  turkeys,  which 
hatch  their  eggs  in  '  hot-beds '  formed  of  large  masses 
of  decaying  vegetable  matters  which  they  heap  together 
for  the  purpose. 

42.  Order  9,  Grallse. — This  group  consists  of  long- 


Storks  and  Ducks. 


legged  birds  which  are  often  waders  in  habit,  and 
are  characterised  by  possessing  small  hind  toes  and 
long  bills.  They  feed  on  worms,  molluscs,  and  fish, 
rarely  on  vegetables.  The  side  of  the  head  presents 
no  bare  patch  between  the  angle  of  the  mouth  and 
the  eye,  and  the  palate  exhibits  a  long  cleft  between 
the  two  lateral  halves  of  the  upper  jawbones.  To  this 
order  belong  the  plovers  and  peewits,  coots  and 
waterhens,  corncrakes  and  snipe,  the  cranes  and 
bustards,  oyster-catchers,  herons,  and  bitterns. 

43.  Order  10,  Storks  (Ciconise). — This  group  also 
consists  of  birds  with  long  legs  and  bills,  which  in 
habit  resemble  the  last,  but  differ  from  them  essen- 
tially in  their  structure.  Thus  they  have  the  two 

FIG.  32.  B 


Head  of  ibis. 


Foot  of  ibis. 


.teral  sides  of  the  upper-jaw  united  along  the  middle 
line  of  the  palate  ;   the  lore  or   space   between  the 
;le  of  the  mouth  and  the  eye  is  bare,  and  the  hind 
is  long  and  functional.    The  best  known  examples 


72  Vertebrata. 

are  the  ibises,  spoonbills,  storks,  and  jabirus,  some  of 
which  are  distinguished  for  their  brilliant  colours, 
like  the  scarlet  ibis,  the  straw-necked  ibis,  and  the 
scarlet  spoonbill.  The  loose  feathers  of  the  lepto- 
ptilus  of  India  are  used  for  ornamenting  bonnets, 
under  the  name  Marabou  feathers. 

44.  Order  11,  Ducks  and  Geese  (Lamellirostres). 
— The  birds  belonging   to   this  order   make  a  very 
natural  assemblage  characterised  by  possessing  webbed 
feet  and  long  flattened   bills,   which   on  the   under 
surface  of  the  upper  mandible  exhibit  a  series  of  close 
transverse  lamellae ;  these  act  as  sensitive  prehensile 
surfaces  in  feeding,  and  large  nerves  are  distributed 
on  them.     They  have  large  fleshy  tongues,  and  the 
hind  toe  is  free  and  small.     The  wild  swan  presents 
a  curious  arrangement  of  its  very  long  and  sinuous 
windpipe,  a  coil  of  which  lies  within  the  hollow  keel 
of  the  sternum.    The  best  known  forms  are  the  ducks, 
geese,  mergansers,  swans,  teals,  widgeon,  &c. 

45.  Order  12,  Longipennes. — These  are  also  web- 
footed   marine   fish-eating  birds,  with  long  pointed 
wings  well  fitted  for  flight.     They  have   long  com- 
pressed beaks,  with  the  nostrils  either  slit-like,  as  in 
the  common  gull,  or  tubular,  as  in  the  petrel.     The 
hind  toe  is  free,  and  usually  of  small  size. 

The  gulls,  terns,  petrels  are  the  best  known 
examples,  the  largest  species  in  the  order  being  the 
famous  albatross,  found  on  the  ocean  about  the 
equator,  which  is  allied  to  the  small  petrels  or  Mother 
Gary's  chickens. 

46.  Order    13,     Pelicans     (Steganopodes). — A 
curious  order  of  water  birds  which  have  all  the  four 


Penguins. 


73 


Foot  of  pelican. 


toes  included  in  the  broad  web,  hence  the  feet  have 
a  singularly  inturned  appearance  (fig.  33).  Many  of 
them  have  long  bills  and  throat  FIG.  33. 

pouches,  like  the  pelicans  and  fri- 
gate birds ;  other  and  better  known 
forms  are  the  gannets,  cormorants, 
and  long-tailed  tropic  birds. 

47.  Order    14,    Pygopodes. — 
The  last  order  of  birds  includes  a 
singular   assemblage    of    seabirds, 
whose  wings  are  small  and  sickle- 
shaped,  scarcely  fitted   for   flight, 
and  sometimes  with  scale-like  fea- 
thers, as  the  penguins  of  the  Ant- 
arctic Ocean.    They  have  the  hind 
limbs  even  farther  back  than   in 

the  generality  of  seabirds,  and  hence  the  curious  erect 
position  assumed  by  these  birds  when  standing ;  they 
have  hard  pointed  compressed  bills,  and  a  small  hind 
toe,  the  three  anterior  toes  are  closely  webbed.  The 
auks  of  the  northern  seas,  the  puffins,  guillemots,  and 
razorbills'  of  our  shores,  are  the  most  familiar  examples. 
The  great  auk  of  the  northern  seas,  is  wingless,  and 
like  the  dodo  has  become  extinct. 

48.  Migration  of  Birds. — Among  birds,  as  among 
fishes,  we  notice  the  curious  habit  of  periodical  mi- 
gration ;  the  travelling  at  regular  periods  into  districts 
wherein  suitable  food  is  abundant,  and  their  return 
on  change  of  season  ;  thus  the  swallows,  swifts,  rice 
birds   and  warblers  visit  the  north  about  the   middle 
of  April,  breed  there,  and  then  return  to  their  winter 
quarters  in  the  Southern  States  and  the  West  Indies 


74  Vertebrata. 

on  the  advent  of  cold  weather,  about  the  first  week  of 
October. 


CHAPTER  XIV. 

CLASS    5,    MAMMALIA. 

49.  General  Characters, — This,  the  highest  class 
of  vertebrate  animals,  includes  all  those  viviparous, 
warm-blooded  animals  which  are  provided  with  super- 
ficial dermal  glands  for  the  purpose  of  secreting  a 
fluid  called  milk  for  the  nutrition  of  the  young  until 
they  are  able  to  seek  out  other  nutriment  for  them- 
selves. They  are  for  the  most  part  terrestrial  in  habit ; 
they  are  all  provided  with  epidermal  covering  in  the 
form  of  hairs  ;  and  the  lower  jaw  in  them  articulates 
directly  with  the  base  of  the  skull,  the  quadrate  bone 
being  very  small  and  included  in  the  ear  cavity,  so 
that  it  is  of  use  only  in  conveying  sound-waves  to  "the 
nerves  of  hearing.  Man,  all  quadrupeds,  seals,  whales, 
and  bats  are  examples  of  this  class. 

The  superficial  clothing  of  hairs  characteristic  of 
the  class  may  be  only  transitory,  as  in  whales  and 
some  thick-skinned  animals,  or  the  hairs  may  be 
thick  and  spine-like,  as  in  the  porcupine  and  hedge- 
hog, or  they  may  be  united  into  scales,  as  in  the 
manis  and  armadillo,  or  on  the  tail  of  a  rat.  Each 
hair  is  the  epidermal  secretion  of  a  single  papilla,  and 
is  a  solid  cylinder  composed  of  long  cortical  or  super- 
ficial cells,  and  rounder  central  cells.  The  hairs  arise 


v> 

Skeleton  of  Mammalia.   ^'/          7-5 


in  pits  or  follicles,  and  into  these Jfpllid^s  ther 
sebaceous  glands,  which  secrete  an  b%-  material 
the  lubrication  of  the  hairs.  >^.         f  . j 

The  neck-region  of  the  vertebral  columKe*  ba£k-j 
bone  in  all  mammals  consists  of  seven  vertebras) 
except  in  three  cases;1  the  back  region  consists 
about  twenty,  but  the  number  is  more  variable;  th 
shoulder  girdle  is  never  connected  directly  to  the 
spine,  but  the  pelvic  girdle  always  is  so,  and  hence 
there  are  always  certain  vertebrae  thickened  and  united 
for  the  purpose  of  supporting  the  pelvis;  these  are 
known  as  the  sacrum,  and  behind  this  in  most 
mammals  is  the  tail,  which  varies  extremely  in  length, 
sometimes,  as  in  the  long-tailed  manis  of  Western 
Africa,  having  over  forty  vertebrae,  in  others,  as  in 
some  bats,  having  only  three.  In  man  there  are  four 
very  small  rudimental  tail  vertebrae,  and  the  same 
number  exists  in  the  gorilla,  chimpanzee,  and  orang- 
outang. In  many  mammals,  as  the  South  American 
mbnkeys,  opossums,  and  kinkajous,  the  tail  is  prehen- 
sile and  is  used  as  an  additional  hand  in  climbing. 

50.  Skeleton. — The  skeleton  consists  of  two  classes 
of  bones,  some  with  an  interior  of  spongy  cells,  others 
ith  an  internal  cavity.  In  both  cases  the  hollow 
,ces  are  rilled  with  marrow.  The  skull  in  mammals 
a  solid  box  to  which  the  upper  jaw  is  immovably 
fixed,  and  it  articulates  with  the  first  vertebra  of  the 
neck  by  means  of  two  articular  knobs  or  condyles. 
The  lower  jaw  is  composed  of  two  pieces  only,  one 
on  each  side,  and  it  forms  a  joint  directly  with  the 

1  These  are  two  sloths,  one  having  9,  the  other  6  vertebrae, 
and  an  aquatic  American  animal,  the  manatee,  which  has  6. 


£ 


76  Vcrtebrata. 

skull,  beneath  the  ear.  The  shape  of  the  articular 
surfaces  which  form  this  joint  is  variable,  and  de- 
pends on  the  nature  of  the  food  and  the  character  of 
the  motions  which  are  necessary  for  mastication. 
Thus,  in  flesh-eating  animals  the  lower  jaw  has  a 
transversely  elongated,  cylindrical  condyle,  which  can 
allow  only  of  a  vertical  motion,  while  in  gnawing 
animals  the  lower  jaw  slides  forwards  and  backwards. 
51.  Teeth. — The  jaw  arches,  and  they  alone,  bear 
teeth,  which  are  arranged  in  one  row  ;  no  accessory 
teeth  are  developed  on  the  palate  as  in  reptiles  and 
fishes.  The  teeth  are  always  in  sockets,  and  are 

FIG.  34. 


Skull  of  anteater,  a  perfectly  toothless  mammal. 

rarely  absent,  as  in  the  anteaters  (fig.  34),  though 
sometimes  they  are  rudimental  and  disappear  early, 
as  in  whales.  There  are  usually  two  sets  of  teeth  ; 
one  an  early  developed  or  milk  set,  which  soon  drop 
out  and  are  succeeded  by  a  second  or  permanent  set ; 
thus  reminding  us  of  what  we  found  in  crocodiles, 
where  successively  growing  teeth  follow  each  other  in 
the  one  row  almost  indefinitely  as  long  as  growth 
continues.  Those  teeth  in  the  upper  jaw  which  are 
rooted  in  the  foremost  bone,  or  premaxilla,  are  called 
incisor  teeth,  and  have  usually  a  cutting  edge  and  a 
single  root.  When  the  first  tooth  in  the  maxilla  or 
jaw  proper,  is  placed  near  the  suture  or  line  of  con- 
tact between  that  bone  and  the  premaxilla,  it  is 


Teeth  of  Mammals.  77 

generally  long  and  pointed  and  has  but  one  root. 
To  it  the  name  canine  is  given,  while  the  other 
maxillary  teeth  have  in  general  two  or  more  fangs, 
and  are  called  grinding  teeth  or  molars.  The  milk 
teeth  are  usually  fewer  than  the  permanent  teeth,  and 
hence  some  of  these  grinders  have  had  predecessors 
while  others  have  not;  those  which  are  secondary 
are  called  premolars,  while  those  which  are  primary 
(the  hindermost),  are  called  molars.  Similar  names 
are  given  to  the  corresponding  teeth  in  the  lower  jaw. 
As  the  teeth  vary  in  number  and  size  in  the  different 
orders  of  mammals,  they  afford  a  good  and  easy 
system  whereby  the  different  forms  can  be  discrimi- 
nated ;  and  in  order  to  be  able  briefly  to  describe  the 
characteristic  dentition  of  any  animal,  zoologists  are 
in  the  habit  of  tabulating  the  number  and  arrange- 
ment of  the  teeth  of  animals  in  a  set  formula ;  thus 

FIG.  35. 


Teeth  of  Tasmanian  devil. 

to  write  the  dental  formula  of  an  animal  we  first  put 
down  the  initials  of  the  sets  of  teeth,  and  follow  each 
initial  by  the  number  of  teeth  of  that  sort  in  the  two 
jaws,  those  of  the  upper  jaw  being  written  like  the 


78  Vertebrata. 

numerator  of  a  fraction,  while  those  of  the  lower  are 
placed  as  the  denominator  ;  thus,  in  an  adult  man 


the  dental  formula  is  7?=^,  Ci=^,  P2-= 

2  -  2  I  -  1  2  —  2  3  -  3 

that  is,  on  each  side  of  each  jaw  there  are  two  in- 
cisors, on  each  side  of  each  jaw  one  canine,  two  pre- 
molars,  and  three  molars.  The  jaws  are  almost 
always  protected  by  fleshy  lips,  except  in  the  first 
order. 

52.  Viscera.  —  Mammals  have  well  developed 
brains,  and  usually  acute  sense-organs.  The  lungs 
and  heart  are  separated  from  the  intestine  and  other 
digestive  organs  by  a  muscular  partition,  called  the 
diaphragm,  which  is  an  important  agent  in  breathing. 
The  heart  consists  of  four  cavities,  and  the  opening 
between  the  right  auricle  and  right  ventricle  is  guarded 
by  a  membranous  valve  consisting  of  three  flaps. 
There  is  but  one  aortic  arch  in  the  adult,  and  it 
arches  to  the  left  side  ;  there  are  two  carotid  arteries 
for  conveying  blood  to  the  brain.  The  blood  con- 
tains round,  non-nucleated  corpuscles,  and  therein 
differs  from  that  of  any  of  the  foregoing  classes. 

There  are  seventeen  orders  of  mammals  at  pre- 
sent living,  but  representatives  of  several  additional 
and  most  remarkable  intermediate  orders  have  been 
found  in  a  fossil  state,  especially  in  the  tertiary  beds 
in  America. 


79 
CHAPTER  XV. 

CLASSIFICATION   OF   MAMMALS. 

53.  Order   1,  Monotremata. — The  first  order  of 
mammals  is  called   Monotremata,  and   includes   two 
remarkable  Australian  forms,  the  platypus   and   the 
spiny  anteater.     They  are  both  small  animals,  being 
about  a  foot  in  length.     Both   have   long   coracoid 
bones  separate  from  the  shoulder-blade  or  scapula, 
which,  bird-like,  reach  as  far  as  the  sternum,  and  the 
two  collar-bones  unite  into  a  single  T-shaped  merry- 
thought-like bone.     In  both  forms  there  are  two  long 
spur-like  bones  articulated  to  the  front  of  the  pelvis 
and  embedded  in  the  abdominal   muscles,   and   in 
both  the  bones  of  the  skull  unite  at  an  early  period 
to  form  a  perfectly  continuous  braincase.     They  are 
also   characterised    by   the    intestine   and    excretory 
organs    opening,   as   in   the   birds,   into   a   common 
cloaca  (hence  the  name  of  the  order).     The  platypus, 
or  Ornithorhynchus,  is  aquatic,  and  has  a  duck-like 
bill  and  two  small,  flat,  horny  teeth  in  each  jaw.    The 
male  has  a  strong  hollow  spur  on  the  ankle  which 
communicates  with  the  duct  of  a  poison  gland  and 
is   a   weapon   of   offence.      The   spiny   anteater,   or 
Echidna  (fig.  36),  is  toothless,  and  has  a  long  slender 
horny  bill,  a  worm-like  tongue,  and  a  dermal  covering 
of  strong  stout  spines.    The  young  of  both  these  forms 
are  born  in  a  very  imperfect  state  of  development 

54.  Order  2,  Marsupialia. — The  second  order  of 
mammals  is  named  Marsupialia,  and  includes  kanga- 


8o 


Vertebrata. 


roos  and  opossums,  and  all   those   other  Australian 
forms  in  which  the  females  bear  on  the  under  surface 


Kangaroos. 


8 1 


FIG.  37. 


of  the  body  a  pouch  wherein  the  young  are  received 

and  sheltered  after  their  birth.     This  pouch  is  sup- 

ported by  two  bones  (fig.  37,  ;;/,) 

similar  to   those   described   in 

connection   with  the  pelvis   of 

the  Monctremes  ;  to  these  bones 

the  name  marsupial  bones  has 

been  given,  but  they  exist  in  the 

pouchless  males  as  well  as  in 

the  pouch-bearing  females.    All 

the    marsupials   are    clad   with 

thick  fur,  and  they  are  armed 

with  claw-bearing  toes,  two  of 

which  on  the   hind   foot   tend 

to  become  very  small  and  united 

within  a  common  web  of  skin. 

They  exhibit  many   characters 

of  inferiority  to  the  other  mam- 

mals ;  thus,  the  two  lateral  lobes 

of    the    fore-brain    are    nearly 

smooth  on  the  surface  and  are 

imperfectly  united  together,  and  the  young  are  born 

in  an  exceedingly  rudimental  state. 

The  marsupials  vary  very  much  in  habit,  and  are 
modified  to  suit  these  habits.  Thus,  the  Tasmanian 
devil  and  Tasmanian  wolf  are  flesh-eaters,  with  sharp 
claws  and  sharp  strong  teeth  (fig.  35).  The  opossums 
of  America  are  insect-eaters,  and  have  sharp  and 
numerous  teeth  ;  they  are  the  only  marsupials  which 
live  outside  the  great  Australian  region,  to  which 
all  the  others  are  confined,  and  of  which  they  are 
almost  the  sole  mammalian  inhabitants.  Some  of 


Pel  vis  of  kangaroo. 
,  marsupial  bones;  62,  mum. 


82 


Vertebratd. 


the  opossums  have  the  pouch   rudimental,  and  the 
mother  carries  her  young  ones  on  her  back,  often 


with  their  prehensile  tails  coiled  round  her 
tail.  Others,  like  the  yapock  of  South 
America,  are  amphibious,  and  have  webbed 
feet. 

The  kangaroos  proper  (fig.  38)  are 
characterised  by  the  enormous  dispropor- 
tion of  the  fore  and  hind  limbs  ;  the  former 
are  short,  five-fingered,  while  the  latter 
are  very  long  with  long  feet,  the  middle  or 
third  toe  (which  corresponds  to  our  fourth, 
as  they  have  no  great  toe)  being  enormous 
in  length,  the  fourth  being  a  little  smaller, 
while  the  first  and  second  are  united  and  excessively 


Kangaroos ',  Phalangcrs.  83 

slender.  The  tail  is  thick  and  with  the  hind  legs 
makes  a  tripod  whereupon  the  animal  rests  when 
standing.  In  feeding,  the  animal  bends  down  so  as 
to  rest  on  the  short  forepaws,  and  in  running  it  pro- 
gresses by  a  series  of  long  leaps  or  bounds  in  which 
it  uses  only  its  hind  legs. 

The  largest  living  kangaroos  are  about  five  to  six 
feet  high  when  standing ;  but  the  majority  of  the 
species  are  small,  some  being  not  larger  than  a  rat 

FIG.  39. 


Teeth  of  kangaroo  rat. 

These  true  kangaroos  are  herbage-feeders,  and  they 
have  a  complexly-pouched  stomach  to  enable  them  to 
digest  green  food.  Their  teeth  generally  are  :  — 


3—  3 


°  rr 
-,  or 


The  phalangers,  or  Australian  opossums,  are  fruit- 
eaters  for  the  most  part,  and  like  the  opossums  of 
America  they  have  an  opposable  thumb  on*the  hind 
foot,  which  thus  is  able  to  act  in  grasping  like  a  hand. 
Some  of  these.  phalangers  have  wing-like  side  folds  of 
skin  stretching  from  the  fore  to  the  hind  limbs,  where- 
by they  are  able  to  take  long  flying  leaps. 


84  Vertebrata. 

The  wombat  is  a  burrowing  and  gnawing  mar- 
supial, whose  chisel-shaped  incisor  and  other  teeth 
continue  permanently  to  grow,  and  thus  the  waste  of 
tooth-tissue  which  takes  place  in  the  process  of  grind- 
ing the  roots  and  twigs  which  constitute  its  food,  is 
restored.  This  animal  is  about  2\  feet  long,  and,  like 
the  koala  or  native  bear  of  Australia,  has  an  accessory 
gland  in  the  stomach,  and  a  long  caecum  or  pouch, 
where  the  large  and  small  intestines  unite.  They  are 
both  also  almost  tail-less,  and  the  koala  has  its  thumb 
and  index  fingers  capable  of  being  opposed  to  the 
others. 

Some  fossil  kangaroos,  like  the  Diprotodon,  were  of 
great  size  ;  one  thigh  bone  of  this  animal  in  the  museum 
of  the  University  of  Dublin,  must  have  been  at  least 
two  feet  in  length  when  complete.  It  is  also  interesting 
that  the  earliest  fossil  mammals  which  have  as  yet  been 
discovered  are  marsupials.  The  bones  of  marsupials 
are,  in  general,  easily  recognised  ;  thus  the  lower  jaw 
has  an  inflexed  angle,  whereby  it  can  be  distinguished 
from  that  of  any  other  mammal.  The  dentitions  of 
marsupials  are  very  variable,  as  can  be  seen  from  the 
four  subjoined  examples  :  — 

Kangaroo  (fig.  37)  7  3=3,  £!= 

—  — 


Wombat  .  7l=i,  c  5=5,  P 


i  —  i        4  —  4 


i  —  i       o  —  o        i  —  i        4  —  4 
~  5 


Myrmecobius   or)  74—  4  r1—1    p2~2 
banded  anteater  j      3—3'      i—  i'      3—3' 


3—3'      i—  i'      3—3'       6—6* 


Tasmanian   devil)   74  —  4  r\  —  i    r>2  —  2 
(%  35)        )  7  3=^'     i=i'     i=? 


—  4 
35) 


85 
CHAPTER  XVI. 

PLACENTAL   MAMMALS. 

55.  The  Placenta. — In  all  the  succeeding  orders 
of  mammals  the  young  are  not  born  until  their 
internal  organisation  has  become  much  more  perfectly 
developed  than  in  the  case  of  the  young  of  the  mar- 
supials and  monotremes ;  and  in  order  to  provide  for 
their  nutrition  while  they  are  thus  growing,  a  peculiar 
vascular  organ,  called  the  placenta,  is  developed, 
whereby  blood  is  supplied  to  the  embryo  for  its 
nourishment;  hence  they  are  called  placental  mam- 
mals to  distinguish  them  from  the  marsupials,  which 
are  named  non-placental  mammals. 

Order  3,  Edentata, — The  third  mammalian  order 
is  known  as  Edentata,  and  includes  the  anteaters  and 
armadillos,  which  are  easily  recognised  by  the  absence 
of  incisor  teeth,  at  least  in  the  middle  of  the  jaws,  so 
that  the  front  of  the  long,  snout-like  mouth  appears 
toothless,  hence  the  name.  They  are  all  armed  with 
strong,  usually  sharp  claws,  and  are  clad  with  coarse 
hair,  or  else  with  hard  scales,  and  feed  on  insects, 
small  animals,  or  carrion.  The  true  anteaters  are 
natives  of  South  America,  and  are  quite  toothless  (fig 
34).  They  have  exceedingly  long,  worm-like  tongues, 
which  they  can  protrude  for  the  purpose  of  entrap- 
ping the  insects  whereon  they  feed  ;  and  they  have 
an  enormous  pair  of  glands  in  the  neck  which  secrete 
a  glutinous  fluid  to  render  the  surface  of  the  tongue 
sticky.  This  long  tongue  they  can  retract  rapidly, 


86 


Vertcbrata. 


FIG.  40. 


and  in  order  to  enable  them  to  accomplish  this,  the 
retractor  muscle  extends  back  to  trie  hinder  end  of 
the  breast-bone,  which  itself  is  often  enormously 
elongated.  Some  anteaters  are  over  five  feet  in 

length,  others  are  much 
smaller.  The  great  Cape 
anteater  of  South  Africa 
is  closely  allied,  but  has 
a  strap-like  tongue  and 
grinding  teeth,  which  are 
peculiar  in  their  struc- 
ture, as  each  tooth  con- 
sists, not  of  a  single 
papilla  like  the  teeth  of 
most  other  animals,  but 
|  of  a  closely  united  bundle 
of  separate  papillae  (fig. 
I  40).  The  pangolins  of 
Africa  and  Asia  are 
covered  with  overlap- 
ping epidermal  scales, 
and  are  also  toothless 
and  insect-eaters.  They 


Tooth  of  Orycterope  or  Cape  Ant- 
eater  magnified,  showing  the  sepa- 
'ate  papillae,  p,  of  which  each  tooth 
is  made  up  ;  d,  dentine,  or  tooth- 
substance  ;  c,  cement. 


all  have  enormous  claws 
on  their  hands  for  tear- 
ing open  the  ant-hills  so 


as  to  reach  their  prey. 
The  second  family,  or  the  armadillos,  are  South 
American,  scale-covered  burrowing  animals,  with 
grinding  teeth  and  a  short  tongue.  They  feed  chiefly 
on  carrion  or  small  animals,  and  their  dermal  armour 
is  arranged  in  transverse  girdles  or  bands  which  may 
be  movable  on  each  other. 


Armadillos.  87 

The  Edentates  now  existing  are  all  of  moderate 
or  small  size,  but  from  the  remains  of  fossil  forms  we 


know  that  some  of  them  must  have  been  of  gigantic 
proportions. 


88 


Vertebrata. 


56.  Order  4,  Bradypoda,  or  Sloths.  —  These  are 
tail-less   animals  inhabiting   South  America.     They 


are  often  united  with  the  Edentates,  from  which  they 


Sloths  and  Manatees.  89 

differ  in  the  possession  of  short  round  heads,  not  pro- 
longed into  a  snout,  with  a  lower  jaw  of  one  piece, 
even  from  a  very  early  age,  and  also  by  having  a  very 
remarkable  down-directed  process  of  the  malar  or 
cheek-bone.  They  are  strictly  vegetable-feeders,  and 
have  sacculated  stomachs.  Their  whole  organisation 
is  adapted  to  an  arboreal  life,  and  they  live  suspended 
from  the  branches  of  trees  by  their  long  and  strong 
hook-like  claws.  They  are  clad  with  coarse  hair  of 
a  dirty  white  or  brownish  colour,  and  have  two  or 
three  toes  only.  The  peculiarity  of  their  neck  verte- 
brae has  been  alluded  to  before  (§  49).  They  have  no 

incisor  teeth  and  ^     *  molars,  which  are  simple  and 

nearly  flat-topped. 

The  Megatherium,  a  fossil  sloth  from  South 
America,  must  have  been  little  less  in  size  than  a 
large  hippopotamus.  In  many  respects  it  and  its 
allies  seem  like  passage  forms  from  the  sloths  to  the 
armadillos. 

57.  Order  5,  Sirenia  or  Manatees,  constitute  a 
small  group  of  sea-weed-eating  marine  animals,  of  a 
somewhat  fish-like  habit  and  form,  usually  found  near 
the  mouths  of  rivers.  They  have  a  thick  skin,  sparsely 
covered  with  bristles,  and  flat-crowned  grinding  teeth. 
They  have  no  hind  limbs,  and  the  fore-limbs  are 
converted  into  paddles.  The  heart  in  some  is  deeply 
cleft,  the  right  and  left  ventricles  being  nearly  separate 
from  each  other  (fig.  43).  One  animal  of  this  group, 
the  Rhytina,  which  inhabited  some  islands  in  Behring's 
Strait,  has  become  extinct  within  the  last  century. 
Another,  the  dugong,  inhabits  the  Indian  Ocean, 


9o 


Vertebrata. 


while  the  manatee  or  mermaid  is  a  native  of  the 
opposite  shores  of  the  South  Atlantic,  extending  from 
South  America  to  Africa.  These  are  often  confounded 
with  whales,  but  can  be  known  therefrom  by  their 


FIG.  43- 


Heart  of  dugong,  showing  the  separation  of  the  ventricles. 

«7,  right  auricle  ;  d,  left  auricle  ;  b,  right  ventricle ;  e,  left  ventricle  ; 
/,  aorta ;  c,  pulmonary  artery. 

possessing  a  neck,  a  movable  elbow-joint,  a  trace  ot 
nails,  and  nostrils  far  forward  and  not  at  the  top  of 
the  head.  They  also,  except  the  extinct  Rhytina, 
possess  teeth. 

58.  Order  6,  Ungulata,  includes  all  those  herbi- 
vorous mammals  whose  extremities  are  used  solely  as 
organs  of  progression,  and  not  of  prehension,  and  in 
which  each  toe  ends  in  a  hoof  or  broad  case  of  horny 
epidermis.  They  are  usually  animals  of  large  size, 
and  they  have  no  collar-bones.  Their  brains,  however, 
are  small  in  proportion  to  the  bulk  of  the  body,  and 


Horse,  Ass,  and  Tapir.  91 

the  intestinal  canal  is  of  very  great  length.  There  are 
two  chief  sub-orders  of  these  hoofed  animals,  the  first 
consisting  of  such  as  have  odd  toes  on  their  hind 
feet,  and  unsymmetrical  toes  on  the  fore  feet.  Of 
these  odd- toed  mammals,  there  are  three  living 
types — horses,  tapirs,  and  rhinoceroses.  The  horse 
and  ass  have  only  a  single  toe  developed  on  each 
limb,  which  corresponds  to  the  third  toe  of  ordinary 
mammals.  They  have  also  a  dentition  of 

,6   ci— i  p4— 4  ^3—3. 

J.       ,     ^/  ,  J.  ,  J.WJL 

6       i— i       4—4        3—3 

The  two  best  known  forms  are  the  horse  and  the 
ass  ;  the  former  is  characterised  by  its  tail,  hairy  from 
its  base,  and  by  the  wart-like  callosities  on  the  inner 
surface  of  its  legs.  Remains  of  horses  are  found  in 
the  bone  caves  of  Britain  and  of  South  America,  as 
well  as  in  those  of  Continental  Europe.  The  striped 
races  of  the  genus  Equus  are  confined  to  Africa ;  they 
are  the  zebra,  the  quagga,  the  dauw,  &c.,  and 
are  scarcely  tameable.  The  wild  asses  inhabit 
Western  Asia.  Fossil  horses  are  known,  exhibiting 
all  the  intermediate  grades  of  development  of  feet 
from  the  single  hoof  of  the  common  horse  to  the 
Eohippus  with  four  functional  toes  and  a  fifth  rudi- 
mentary one  on  the  fore  feet,  and  three  toes  behind. 
The  tapirs,  natives  of  Malaya  and  of  South  America, 
are  also  uneven-toed  ungulates,  possessing  three  toes 
on  their  hinder,  and  four  (but  laterally  unsymmetrical) 
toes  on  their  fore  feet.  They  are  characterised  by 
ossessing  a  proboscis-like  snout,  and  rather  long 
gs.  In  number  the  teeth  are  equal  to  those  in  a 
Drse. 


92  Vertebrata. 

The  rhinoceros  (fig.  44)  is  the  third  type  of  this 
sub-order,  and  is  a  native  of  Africa  and  the  Malay 


archipelago;  the  foot  is  three-toed,  and  the  skin  of 


Rhinoceros,  Swine.  93 

enormous  thickness  and  often  folded.  The  leading 
characteristic  is  the  long  epidermal  horn  which  is 
rooted  in  the  dermis  on  the  upper  surface  of  the  nose. 
This  in  structure  consists  of  a  tuft  of  confluent  hairs, 
and  sometimes  grows  to  several  feet  in  length,  and  is 
of  great  hardness;  the  horn  is  always  medial,  and 
usually  single,  when  two  exist  they  are  placed  one  in 
front  of  the  other.  At  one  time  a  species  of  rhino- 
ceros clothed  with  a  woolly  coating  inhabited  Great 
Britain  and  the  northern  parts  of  Europe  and  Asia, 
but  it  became  extinct  in  prehistoric  times. 

All  these  odd-toed  ungulates  have  at  least  twenty- 
two  vertebrae  in  their  trunk,  interposed  between  the 
neck  and  the  sacrum,  and  they  all  have  a  bony  knob 
or  third  trochanter  on  the  outside  of  the  shaft  of  the 
thigh  bone  for  the  attachment  of  muscles.  See  fig. 
44,  also  fig.  41. 

The  second  sub-order  of  hoofed  animals  includes 
those  whose  toes  are  in  even  numbers,  two  or  four, 
and  are  laterally  symmetrical  (when  there  are  four, 
two  are  in  front  and  two  behind).  They  have  for  the 
most  part  nineteen  dorso-lumbar  vertebrae,  and  none 
of  them  have  the  protuberance  on  the  thigh-bone 
referred  to  above.  Many  of  them  have  horns,  but 
these  are  always  on  the  forehead,  and  one  on  each 
side,  never  median  as  in  the  rhinoceros. 

59.  Swine  and  Hippopotami. — There  are  two  very 
well-marked  divisions  of  these  even -toed  ungulates. 
In  one  of  these  the  animals  have  simple  stomachs, 
and  the  grinding  teeth  have  little  knobs  or  protuber- 
ances on  their  surfaces,  hence  these  are  called  Buno- 
donts  -}  in  the  other  group  the  stomachs  are  complex, 


94  Vertebrata. 

and  the  hardest  layer  of  the  teeth  (the  enamel),  is 
arranged  in  crescents;  these  are  known  as  Ruminants. 
FIG  Of  the  bunodonts  the  pigs  are  the 

most  familiar  examples.     Our  domes- 
tic  pigs   are   derived  from  the  wild 
boars  of  Southern  Europe  and  Asia, 
animals    which     formerly    inhabited 
Great  Britain  in  a  wild  state.     The 
babyroussa  of  the  Malay  Islands  is 
Crown  of  the  tooth  of  a  singular  pig  whose  upper  canine 
eanamericsrhe°s±i.the  teeth  grow  upwards  and  arch  back- 
wards  so  as   to  reach   the  forehead 
where  they  end  in  a  curled  point.     Most  of  the  pigs 
have  large  tusk-like  canines,  and  their  teeth  are  usually 
represented  by  the  formula 

3   c  L 


3—3       i  -i       3—3        3—3 

The  hippopotamus  of  the  rivers  of  Africa  is  an 
enormous  pig-like  creature,  with  very  short  legs  and 
a  heavy  body,  and  with  long  tusk-like  incisors,  two  in 
each  jaw  ;  it  sometimes  reaches  a  length  of  nine  feet. 
60.  Ruminants,  —  The  ruminants  are  so  called 
because  they  chew  the  cud,  that  is,  they  subject  their 
food  to  a  second  chewing  after  it  has  been  swallowed. 
They  are,  for  the  most  part,  large  soft-fleshed  animals, 
the  favourite  prey  of  large  carnivores,  and  as  the  food 
which  they  require  for  their  nourishment  is  bulky, 
being  green  herbage,  and  only  to  be  obtained  in  open 
places  of  pasturage,  where  they  would  be  exposed 
without  shelter  to  the  assaults  of  their  enemies,  it 
becomes  a  matter  of  vital  importance  for  their  well- 


Stomachs  of  Ruminants. 


95 


being  that  the  process  of  mastication,  a  long  and 
tedious  one  in  the  case  of  such  food,  should  be  kept 
over  until  the  animal  has  laid  in  its  store  of  provisions 


and  retired  to  a  sheltered  hiding-place.     Accordingly 
the  stomach  of  a  ruminant  is  divided  into  four  com- 


96  Vertebrata. 

partments,  and  into  the  first  of  these  (called  the 
paunch}  the  food  is  taken  when  first  swallowed  ;  then 
it  passes  into  the  second  division,  which  consists  ot 
many  large  hexagonal  cells  or  little  chambers ;  here 
it  becomes  divided  into  masses  for  re-chewing,  and 
these  pass  up  the  oesophagus  back  into  the  mouth, 
where  it  is  carefully  and  slowly  masticated,  and  mixed 
with  saliva,  after  which  it  is  re-swallowed,  but  this  time 
as  a  semi-fluid  soft  material,  which  on  reaching  the 
stomach  is  conducted  along  a  gutter  made  by  a 
mucous  fold,  into  the  third  stomach  or  liber,  which 
consists  of  many  layers  of  mucous  membrane  arranged 
like  the  leaves  of  a  book.  Here  the  materials  are  still 
farther  mixed  up  with  the  secretions  of  gastric  glands, 
and  pass  on  into  the  fourth  stomach,  where  digestion 
finally  takes  place.  The  camels  of  Arabia  and  Africa 
differ  from  the  other  ruminants  in  having  no  third 
stomach,  in  possessing  canine  teeth  in  each  jaw,  and 
two  lateral  incisor  teeth  in  the  upper  jaw.  They  have 
also  nails  rather  than  hoofs  on  their  large  and  well- 
padded  toes.  The  hump  on  the  camel's  back  consists 
of  fat  and  cellular  tissue.  There  is  a  single  hump  on 
the  dromedary,  but  there  are  two  on  the  back  of  the 
Arabian  or  Bactrian  camel.  The  second  stomach  of 
the  camel  has  deep  cells  or  compartments,  which  has 
given  origin  to  the  fables  about  the  capacity  of  camels 
to  store  water  in  their  stomachs. 

The  llamas  of  the  Andes  in  South  America  are 
closely  allied  to  the  camels,  and  agree  with  them  in 
most  of  their  peculiarities,  but  have  no  humps.  The 
musk-deer,  which  inhabit  the  mountainous  regions 
between  the  Himalaya  and  the  Altai  mountains,  have 


The  Cow. 


97 


canine    teeth,  and    are    distinguished    by  the 
presence  of  a  pair  of  odour-secreting  musk-glands. 


98  Vertebrata. 

The  other  ruminants  have  neither  canine  nor 
incisor  teeth  in  the  upper  jaw,  and  most  of  them 
possess  horns.  In  the  giraffe,  the  tallest  arid  longest- 
necked  of  the  mammals,  these  horns  are  short  pro- 
cesses of  the  frontal  bone  covered  with  hairy  skin. 
In  the  cows,  antelopes,  goats  and  sheep,  these  horns 
are  made  up  of  an  outer  hard,  horny  sheath,  placed 
over  a  bony  core  or  process  of  the  frontal  or  forehead 
bone.  In  the  ox  and  cow  group,  the  horns  are 
directed  forwards,  and  are  smooth,  while  in  the 
antelopes,  which  are  mostly  natives  of  Africa,  the 
horns  are  directed  backwards,  and  are  often  ringed 
or  waved.  One  American  species,  the  pronghorn, 
sheds  its  horns  periodically  like  the  true  deer.  The 
goats  and  sheep  have  compressed  angular  wrinkled 
horns,  often  coiled.  Our  domestic  sheep  are  possibly 
derived  from  the  mountain  sheep  of  South  Europe 
and  Asia. 

The  deer  family  possess  solid  horns  composed  of 
bony  processes  of  the  frontal  bone,  often  branched  in 
various  ways.  These  antlers  are  annually  shed  and 
renewed,  each  new  growth  being  usually  larger  than 
ics  predecessor.  The  best  known  examples  are  the 
Virginian  deer,  the  fallow  deer,  and  the  roebuck. 
In  most  of  these  ruminants  the  dentition  is  repre- 
sented by  the  formula 

7  o_o  co_o       3_3       3_3 

3—3       i— i       3—3       3—3 


99  /vy 

CHAPTER    XVIL 

'  '  t          *  *  *S' 

CLASSIFICATION   OF   MAMMALS — COtltulued. 


61.  Order  7,  Cetacea  (Whales).— These,  like ' 
Sirenia,  are  marine  mammals  with  no  hind  limbs,  and 
having  the  fore  limbs  converted  into  fins.  They  are 
fish-like  in  shape,  without  necks,  and  have  a  smooth 
thick  skin  beneath  which  is  a  thick  layer  of  fat  known 
as  blubber.  The  nostrils  are  situated  on  the  upper 
surface  of  the  head,  and  are  called  blow-holes,  and 
are  well  protected  by  dermal  folds  so  as  to  prevent 
the  entrance  of  water  into  the  air-passages  while 
the  whale  is  beneath  the  surface  of  the  sea.  These 
animals  require  to  rise  to  the  surface  to  breathe,  and 
on  doing  so  they  forcibly  eject  a  shower  of  spray, 
consisting  of  the  mucus  secreted  by  the  membrane  of 
the  nasal  passages,  the  vapour  of  the  breath,  and 
whatever  sea  water  lurks  in  the  crevices  about  the 
nostril ;  this  process  is  called  blowing,  and  it  is  in 
reality  somewhat  like  a  forcible  sneeze  preparatory  to 
a  deep  inspiration.  The  sense  of  smell  is  almost  or 
altogether  absent.  There  are  seven  cervical  vertebrae, 
but  they  are  usually  united  together  so  as,  in  old 
whales,  to  form  one  bone. 

The  tail  in  whales  consists  of  two  lateral,  hori- 
zontally-placed lobes  consisting  of  folds  of  skin  and 
connective  tissue  appended  to  the  end  of  the  vertebral 
column  ;  this  is  the  chief  instrument  of  locomotion. 

The  mouth  in  true  whales  is  of  enormous  capacity, 
and  as  theii  food  is  mostly  small  fish,  cuttlefishes  and 


ioo  Vertebrata. 

molluscs,  they  require  to  take  in  very  large  quantities 
of  this  material  for  their  nourishment,  which  they  do 
in  the  following  way.  The  jaw  arches  are  covered  all 
around  their  edges  with  horny  plates  of  '  whalebone/ 
fringed  with  bristles  in  place  cf  teeth,  and  these  act 
as  strainers.  In  feeding,  the  animal  opening  its  mouth, 
takes  in  a  mouthful  of  sea-water  and  its  animal 


FIG.  48. 


Head  and  tongue  of  whale. 
a,  tongue  (represented  much  too  large)  ;  b,  whalebone  plates. 

contents,  and  then  by  closing  the  jaws  and  pressing 
the  tongue  against  the  palate,  expels  the  water  through 
the  slits  between  the  whalebone  plates,  which  by  their 
opposition  and  by  their  bristly  margin  retain  the  solid 
materials  to  be  subsequently  swallowed. 

In  some  whales  there  are  exceedingly  minute 
rudiments  of  the  hind  limbs,  in  the  form  of  small 
ischia  or  pelvic  bones,  embedded  in  the  muscles  of 
the  abdomen,  and  not  visible  on  the  surface. 

Whales  have  usually  complex  stomachs,  often 
with  four  chambers;  they  have  also  a  moderately  long 
alimentary  canal,  large  and  tortuous  networks  of  blood- 
vessels along  the  ribs,  and  a  thick  fleshy  diaphragm. 


Seals  and  Walruses.  101 

The  large-headed  sperm  whales  are  often  as  much 
as  sixty  to  eighty  feet  long.  One  third  of  the  whole 
length  is  formed  by  the  head,  whose  anterior  bones, 
enormously  dilated,  are  hollowed  into  a  chamber" 
which  contains  the  substance  called  spermaceti,  used 
in  making  ointments  and  cosmetics.  These  whales 
possess  from  fifty  to  sixty  large  conical  teeth  in  the 
lower  jaw,  and  therein  differ  from  the  baleen  whales, 
which  in  some  cases  possess  small  embryonic  teeth 
that  disappear  early  and  are  replaced  by  the  whale- 
bone plates.  The  common  porpoises,  bottle-noses, 
and  dolphins  have  numerous  simple  teeth  in  both 
jaws,  and  the  narwhal  has  one  enormous  front  tooth 
which  sometimes  grows  to  a  length  of  5^  or  6  feet, 
forming  a  horizontal  tusk.  Whales  are  the  largest  of 
animals,  and  have  been  seen  over  ninety  feet  in 
length. 

62.  Order  8,  Pinnipedia. — This  small  order  con- 
sists of  the  seals  and  walruses,  and  forms  a  connecting 
link  between  the  whales  on  the  one  hand  and  the  bears 
on  the  other.  They  are  aquatic,  fish-eating,  hair-clad 
mammals,  with  four  fin-like  limbs,  each  provided  with 
five  webbed  digits.  The  hind-limbs  are  stretched 
horizontally  backwards  on  the  same  line  as  the  tail, 
to  which  they  are  very  closely  united.  They  have 
roundish  heads  provided  with  numerous  sensitive 
bristles,  large  eyes,  and  loosely  united  facial  bones. 
They  have  valvular  nostrils,  no  external  ears,  simple 
stomachs,  and  large  venous  cavities  to  hold  the 
impure  blood  while  respiration  is  suspended  during 
diving. 

Most  seals  are  marine,  but  some   live  in  fresh- 


IO2 


Vertebrata. 


water  lakes  as  in  Lake  Baikal.  Our  common  seal  is 
inoffensive  and  easily  tamed.  The  walrus,  known  by 
its  huge  tusks  or  canine  teeth,  used  for  digging  up 
the  molluscs  on  which  it  feeds,  sometimes  reaches 
twenty  feet  in  length.  The  fur  seals,  whose  beautiful 
sk  ns  are  of  such  commercial  importance,  are  natives 
of  the  Southern  Atlantic  and  Pacific  Oceans.  The 
dentition  of  the  common  seal  is 


/  3=3   C-1^1,  ^3=3  j/3zi3. 

2  -  2  I  -  1          3  -  3  2  -  2 

63.  Order  9,  Carnivora,  —  The  flesh-eating  mam- 
mals are  the  cats,  dogs,  weasels  and  bears,  known  by 
possessing  sharp  claws,  long  pointed  canine  teeth,  a 
simple  stomach,  and  a  short  intestine.  The  lower 
jaw  is  constructed  to  move  only  in  the  vertical  plane 
up  and  down,  having  no  lateral  motion,  the  condyle 


FIG.  49. 


Skull  of  lion. 
7,  median  temporal  crest ;  12,  post- orbital  process ;  15,  nasal  bone. 

being  transversely  lengthened.     The  molar  teeth  are 
ridged  and  sharp,  so  as  to  be  fitted  for  dividing  flesh. 


They  nevei 


Cats,  Dogs,  Lions.  103 


hey  never  have  collar-bones.  The  skull  of  a 
carnivore  can  be  easily  known  by  the  prominent 
medial  crest  for  the  attachment  of  the  powerful 
muscles  which  move  the  lower  jaw  (fig.  49,  7). 

The  dog  is  a  typical  carnivore,  whose  teeth  are 
represented  by  the  formula 


1=1^4 


-4 


3—3       i— i       4—4       3—3 

In  progression  dogs  are  digitigrades,  that  is  they  only 
rest  on  the  last  joint  of  their  toes  in  walking,  and 
their  claws  are  blunt,  not  capable  of  being  retracted. 
The  numerous  races  of  dogs  cannot  be  sharply 
marked  off  from  each  other,  nor  can  some  of  the 
varieties  of  the  dog  be  sharply  differentiated  from 
wolves.  The  wolf  has  usually  erect  ears  and  larger 
teeth,  but  no  absolute  point  of  difference  can  be 
relied  upon.  The  fox  has  an  oval  pupil  and  a  more 
bushy  tail.  All  the  true  dogs  have  comparatively 
smooth  tongues. 

The  family  Felidcz,  or  cats,  are  also  digitigrade 
carnivores,  but  they  differ  from  the  Canida,  or  dogs, 
in  having  the  claws  capable  of  retraction  when  not  in 
use,  and  thus  they  are  preserved  from  undue  friction 
and  are  sharp  ;  the  retraction  is  accomplished  by 
mean 3  of  lateral  elastic  ligaments.  The  cats  are 
more  purely  flesh-eaters  than  the  dogs,  and  usually 
hunt  and  kill  their  prey  ;  their  dentition  is 

I  3     3   £ * I  pZ     3  j^r1 * 
3— 3'      i— i'      2—2'      i  — i" 

The  lion  is  a  native  of  Africa  and  Asia,  the  tiger,  the 


IO4  Vertebrata. 

strongest  of  the  carnivores,  is  confined  to  Asia, 
Other  forms  are  the  panthers  and  leopards,  the  ounce, 
the  jaguar  or  American  leopard,  the  puma  or 
American  lion,  the  tiger-cats,  ocelots,  lynx,  and 
domestic  cats.  This  last-named  is  probably  the 
descendant  of  the  wild  cat  of  Abyssinia  tamed  by  the 
ancient  Egyptians.  The  wild  cat  of  this  country 
(Lynx  canadensis),  ranges  over  the  entire  continent 
south  of  the  Arctic  circle.  The  cheetah,  or  hunting 
leopard  of  India,  has  only  partially  retractile  claws. 
The  cats  have  all  rough  tongues  armed  with  numer- 
ous sharp,  recurved  papillae. 

The  hyaenas  are  intermediate  in  some  respects 
between  the  dogs  and  the  cats.  They  have  the 
dentition  and  rough  tongues  of  the  cats,  with  a  more 
doglike  form  and  non-retractile  claws.  They  are 
nocturnal,  and  can  be  known  by  the  peculiarly  low 
hind-quarters  in  comparison  with  the  fore. 

Civets  and  mongooses  make  another  family  called 
Viverrida,  which  usually  possess  odorous  glands, 
rough  tongues,  short  legs,  and  a  semi-plantigrade 
mode  of  progression.  The  weasel  and  otter  family, 
Mustelidcz,  differ  from  these  in  their  shorter,  rounder 
heads,  smooth  tongues,  and  longer  bodies.  Many  of 
these  are  sought  for  on  account  of  their  skins,  such  as 
the  vison,  ermine,  sable,  mink,  &c.  Others,  like  the 
weasel,  skunk  and  pole-cat,  are  well-known  vermin ; 
the  Mustela  foina^  or  marten,  was  the  domestic  cat  of 
the  classic  authors. 

The  plantigrade  carnivores  are  those  that  bring 
their  whole  foot- sole  to  the  ground  when  walking; 
they  are  bears,  badgers,  and  kinkajous.  The  badgers 


Bears,  Badgers,  Kinkajous. 


105 


have   scent  glands,  whereby  they  are  easily  distin- 
guished.    The  kinkajou,  a  native  of  South  America, 


has  a  prehensile  tail  and  retractile  claws.    The  best 


IO6  Vertebrata. 

known  of  the  bears  are  the  polar  or  white  beai  of  the 
Arctic  regions,  the  black  bear  of  America,  the  brown 
bear  of  Europe,  and  the  grizzly  bear  of  the  Rocky 
Mountains,  possibly  the  same  as  the  giant  cave  bear, 
now  extinct  in  these  countries.  The  brown  bear 
formerly  inhabited  the  British  Islands,  but  was  extir- 
pated in  Scotland  in  the  eleventh  century. 

The  bears  differ  from  the  other  carnivores  in  the 
possession  of  tubercled  teeth  which  can  be  used  for 
masticating  vegetable  matters,  and  many  of  them  are 
capable  of  partaking  of  a  mixed  diet. 

64.  Order  10,  Hyracoidea. — A  small  order  inclu- 
ding a  few  little  tail-less  animals,  natives  of  Africa  and 
Syria,  one  of  which  is  the  cony,  mentioned  in  the 
Bible.  They  are  somewhat  rabbit-like  in  habit,  with 
four  toes  on  the  fore  feet,  and  three  on  the  hinder, 
each  toe  being  armed  with  a  flat  nail.  The  molar 
teeth  have  been  compared  in  pattern  to  those  of  the 
rhinoceros,  and  there  are  no  canines.  They  have 
sacculated  stomachs  and  no  collar-bones. 
.  65.  Order  11,  Rodentia.— Gnawing  animals,  the 
largest  order  in  the  entire  class,  including  the  rats,  mice, 
squirrels,  &c.  They  are  all  small  and  claw-bearing, 
and  have  a  most  remarkable  dentition.  There  is 
usually  but  one  incisor  on  each  side  of  each  jaw,  and 
this  tooth  is  chisel-shaped  ;  it  consists  of  two  materials, 
one  a  hard  substance  or  enamel  on  the  outside  or 
front,  the  other  a  softer  dentine  or  bone-like  substance 
behind.  In  their  growth  the  upper  and  lower  teeth 
oppose  each  other,  and  the  constant  friction  during 
feeding  wears  away  the  surface  of  the  tooth,  which 
however  is  constantly  growing,  but  as  the  soft  dentine 


*eeth  of  Gnawing  Mammals. 


107 


wears  away  more  quickly  than  the  harder  enamel,  the 
tooth  is  kept  constantly  sharp ;  hence  when  one 
incisor  in  a  rodent  is  broken,  the  one  that  should 


FIG.  51. 


Flying  squirrel. 


oppose  it  grows  on  continuously,  and  sometimes  this 
mode  of  growth  locks  the  jaws  together. 

There  are  no  canine  teeth  in  rodents,  and  the 


io8  Vertebrata. 

molars  are  separated  from  the  incisors  by  a  long 
interspace.  The  lower  jaw  is  large,  and  its  condyle 
is  so  articulated  as  to  permit  it  to  slide  backwards 
and  forwards  in  mastication,  thus  giving  the  power  of 
gnawing. 

FIG.  52. 


Skull  of  porcupine,  showing  v,  the  large  infra-orbital  cavity. 

Rodents  have  small,  smooth  brains,  usually  a 
simple  or  saccular  stomach,  and  a  long  caecum  or 
blind  pouch  from  the  intestine  (except  in  dormice). 
Some  genera,  like  guinea-pigs,  hares,  and  rabbits,  have 
no  collar-bones,  others,  like  squirrels  and  beavers, 
have  these  bones  well  marked.  The  hares  and  rabbits 
have  a  thin  layer  of  enamel  surrounding  the  backing 
of  dentine  on  the  incisor  teeth,  and  have  two  small 
incisors  behind  the  large  ordinary  pair  in  the  upper 
jaw. 

The  squirrel  family  are  usually  long-tailed  elegant 
creatures,  and  in  one  genus,  the  flying  squirrel  (fig.  51), 
there  is  a  lateral  parachute  of  skin  stretching  from  the 
fore  to  the  hind  limbs.  The  beavers  have  flat  scaly 
tails  and  webbed  hind  feet.  The  rats  and  mice 


Gnawing  Animals. 


109 


are  known  by  their  long  cylindrical  scaly  tails,  and 
usually  rooted  teeth  (except  in  the  voles).  The 
common  grey  rat,  introduced  from  the  banks  of  the 


FIG.  53. 


The  spalax,  or  blind  rat. 


Volga  in  1727  into  Western  Europe,  has  now  nearly 
exterminated  the  black  rat.  Spalax  (fig.  53),  the  rat- 
mole  of  SE.  Europe  and  NW.  Asia,  has  rudimental 
eyes  covered  by  the  skin,  and  Dipus,  the  jerboa  of  the 
East,  has  long,  kangaroo-like  hind  legs  and  very 
small  fore  legs.  The  porcupines  have  a  covering  of 
quill-like  hairs,  and  have  an  enormous  hole  in  the  front 
of  the  skull  wall,  directly  under  the  eye  (fig.  52),  which 
is  partly  occupied  by  a  muscle  of  mastication.  The 
chinchillas,  coypu,  &c.  which  are  sought  for  their  fur, 
are  also  examples  of  this  order. 

Hybernation. — Many  rodents,  like  some  mam- 
mals of  other  orders,  bears,  bats,  &c.,  spend  their 
winter  in  a  condition  of  sleep :  this  process  is  called 
hybernation.  Previous  to  retiring  to  this  rest,  these 
animals  store  up  fat  in  different  regions  of  the  body, 


no 


Vertebrata. 


especially  in  a  large  gland  called  the  thymus,  placed 
in  the  thorax,  or  cavity  of  the  chest,  in  front  of  the 
heart.  This  fat  is  absorbed  during  the  winter,  and 
the  animal  arises  next  spring  lean  and  hungry.  The 
lemmings  extend  far  north  into  the  Arctic  regions, 
some  having  been  captured  at  the  winter  quarters  of 
the  'Alert '  in  1875,  in  N-  latitude  82°. 

66.  Order  12,  Proboscidea  (Elephants).  —  No 
groups  of  mammals  appear  more  diverse  from  each 
other,  in  size  at  least,  than  do  the  rodents  and  the 
elephants,  and  yet  the  latter  are  structurally  more 

FIG.  54. 


Skull  of  young  elephant. 

22,  the  premaxillary  bone,  containing  the  root  of  the  tusk  k  \  15,  nasal  bone  ; 
7,  tempora  region  :  26,  zygomatic  arch ;  i,  lower  jaw  ;  c,  upper  jaw. 

closely  allied  to  the  former  than  to  any  other  order 
of  mammals.     The  elephants  are  the  giants  among 


Elephants.  _ 


in 


living  land  animals  of  the  tropics,  and  are  covered 
with  a  thick  naked,  or  sparsely  haired  skin.  They 
have  five  hoof-covered  toes  on  each  foot,  though 
sometimes  two  toes  are  included  in  one  hoof.  The 
proboscis,  or  trunk,  is  a  muscular  and  exceedingly 
movable  double-barrelled  tube  appended  to  the  nose, 

FIG  55- 


Section  of  the  skull  of  the  elephant,  showing  the  small  size  of  the  brain- 
case,  e,  and  the  large  size  of  the  air  spaces. 

b,  marks  the  posterior  nostrils  ;    13,  the  cavity  of  the  nose  ;  «,  the  front 
opening  of  the  bony  nostrils  to  the  edge  of  which  the  trunk  is  attached. 

in  fact  an  extension  of  that  organ,  which,  by  means 
of  a  finger-like  appendage  at  the  tip,  can  pick  up  even 


112  Vertebrata. 

exceedingly  small  objects.  The  teeth  of  an  elephant 
consist  of  two  tusks  or  incisors  in  the  upper  jaw, 
which  grow  continuously,  sometimes  to  enormous 
sizes,  and  furnish  the  ivory  of  commerce.  There  are 
no  incisors  in  the  lower  jaw,  but  there  are  on  each 
side  of  each  jaw  two  large,  rough-crowned,  quadrate 
teeth,  whose  crowns  are  marked  by  transverse  enamel 
ridges,  used  in  grinding  the  twigs  and  shoots  of  trees 
on  which  these  animals  feed.  There  is  a  constant 
succession  of  these  molars,  seven  of  which  are  de- 
veloped during  the  life  of  the  animal  on  each  side  of 
each  jaw,  but  never  more  than  two,  or  at  most  three, 
are  laterally  functional  at  one  time.  The  skull  is 
enormous,  most  of  its  bulk  consisting  of  huge  air- 
cells,  and  the  brain  is  large  and  convoluted  on  the 
surface.  Two  species  of  elephants  are  now  living, 
confined  to  the  tropics :  one  in  Africa,  known  by  its 
convex  forehead  and  flapping  ears  ;  one  in  India, 
which  has  a  concave  forehead  and  smaller  ears. 
Formerly  several  species  of  elephants  lived  in  Europe, 
and  remains  of  one  form  have  been  abundantly  met 
with  in  some  parts  of  the  British  Islands.  In  Siberia, 
also,  there  exist  numerous  remains  of  a  hair-clad  ele- 
phant, the  mammoth,  which  had  probably  existed 
down  to  a  comparatively  modern  time. 


CHAPTER  XVIII. 

LEMURS,  MOLES,  AND   BATS. 

67.  Order  13,  Prosimii. — The  lemurs,  which 
constitute  this  little  order,  are  monkey-like  animals, 
chiefly  confined  to  the  Island  of  Madagascar,  and  to 
other  islands  in  the  Indian  Ocean.  They  are  arbo- 
real, fruit-  or  insect-eating  animals,  with  an  opposable 
thumb  on  the  fore  foot,  and  sometimes  on  the  hind 
foot  as  well,  the  second  toe  of  which  always  bears  a 
long  claw,  while  all  the  others  usually  have  flat-nails 
like  those  on  the  human  ringers.  In  some  respects 
the  animals  resemble  the  sloths  of  the  New  World, 
and  many  of  them  are  nocturnal.  Their  teeth  are 
always  of  the  four  kinds,  and  are  more  numerous 
than  those  of  man.  They  are  clad  in  an  exceedingly 
soft  and  thick  fur,  and  many  of  them  have  bushy  tails, 
while  others,  like  the  Loris,  or  slow  lemurs,  are  per- 
fectly tailless.  The  largest  forms  measure  about  three 
feet  in  length,  but  some  are  much  smaller,  being  only 
a  few  inches  long.  Many  zoologists  regard  them,  on 
account  of  their  opposable  thumbs,  as  closely  allied 
to  the  monkeys  \  but  in  their  simple  brains  and  in 
the  structure  of  some  of  their  internal  organs,  they 
represent  a  much  lower  grade  of  organisation  than 
that  of  the  monkeys.  The  aye-aye  of  Madagascar,  a 
strange  little  animal,  about  the  size  of  a  rabbit,  has 
nails  only  on  its  thumbs,  and  claws  on  the  other 
fingers.  One  singular  genus  from  the  Philippine  and 


Vertebrata. 


FIG.  56. 


Malay  Islands,  Tarsius,  has  the  tarsus  or  ankle-bones 
of  the  foot  exceedingly  long,  like  the  corresponding 
bones  in  the  frog,  so  that  it  appears  to  have  two  ankle 
joints. 

68.  Order  14,  Insectivora. — This  order  of  mam- 
mals consists  of  the  shrews,  moles,  and  hedgehogs, 
which,  as  their  name  implies,  feed  on  insects  and 
worms,  and  other  small  animals.  They  are  all  of 
small  size,  and  possess  strong  claws,  long  tapering 
snouts,  and  numerous  sharply  pointed  teeth,  the 
canines  being  small  or  absent.  They  all  possess 
complete  collar  bones,  a  character  which  distinguishes 

them  from  Carnivores, 
and  gives  to  the  fore- 
limbs  a  fixity  and  defi- 
niteness  of  action  that 
would  be  otherwise 
wanting.  Their  brains 
are  usually  small  and 
smooth,  not  unlike 
those  of  rodents.  In 
habit  they  are  planti- 
grade, terrestrial,  and 
usually  active.  The 
moles  are  familiar  in- 
stances, and  present  in 
the  highest  degree  the 
character  of  a  fossorial  or  digging  animal ;  the  paddle- 
like  hand  the  square  arm-bone  or  humerus  (fig.  56, 
53),  and  the  enormous  muscularity  of  the  fore-limb 
enable  it  to  dig  with  wonderful  celerity  in  pursuit  of 
the  worms  and  insects  on  which  it  feeds,  while  the 


Bones  of  fore-limb  of  mole. 

52,  scapula  ;  53,  humerus  ;  54,  55, 
fore-arm  bones. 


Moles  and  Bats.  1 1 5 

velvety  skin,  and  the  rudimental  eyes  and  outer  ears, 
give  it  the  greatest  degree  of  fitness  for  its  subter- 
ranean life.  Moles  are  common  in  America  and 
Great  Britain,  but  are  absent  from  Ireland.  The 
shrew-mouse  and  the  hedgehog  are  equally  common 
types ;  the  former  can  be  easily  distinguished  from 
the  true  mice  by  the  structure  of  the  teeth.  The  pigmy 
shrew  of  S.E.  Europe  is  the  smallest  known  mammal, 
being  only  about  two  inches  long.  The  flying  lemurs 
of  the  East  Indian  archipelago,  which  form  the  last 
family  of  this  order,  have  a  wide  parachute-like  mem- 
brane stretching  from  the  fore-limbs  to  the  hind,  and 
thence  to  the  tail.  They  form  a  connecting  link  be- 
tween this  order  and  the  next. 

69.  Order  15,  Cheiroptera  (Bats). — This  curious 
group  of  mammals  includes  the  only  forms  in  the 
entire  class  which  have  any  true  powers  of  flight,  the 
so-called  flying  phalangers,  flying  squirrels,  and  flying 
lemurs  having  only  the  power  of  taking  long  leaps, 
In  the  bats  the  fore  limbs  are  very  long,  the  fingers 
are  enormously  lengthened,  and  are  united  together 
by  an  extensive  and  thin  membrane,  which  stretches 
from  finger-tip  to  finger-tip,  and  from  thence  to  the 
hind  limb;  the  thumb  alone  is  free,  and  it  is  always 
armed  with  a  claw.  The  outline  of  this  membrane 
is  shown  by  the  dotted  line  in  fig.  57.  They  are 
mostly  nocturnal,  with  smooth  brains  and  feeble 
powers  of  sight,  and  are  rarely  of  large  size.  To 
move  the  wings  they  are  provided  with  powerful 
pectoral,  or  breast  muscles,  and  there  is  often  an  im- 
perfect keel  on  the  sternum,  for  muscular  attachment. 
They  have  also  long  and  strong  clavicles.  Their  hind 

I  2 


Vertebrata. 


limbs  are  turned  outwards  in  a  peculiar  manner,  so 
that  the  knees  bend  backwards,  and  the  great  toes  are 


Bats.  117 

thus  twisted  to  the  outer  side  of  the  foot,  which  has 
five  equal  claw-bearing  toes.  Many  bats  have  enor- 
mous ears,  others,  like  the  vampires  of  South  America, 
have  sensitive  leaf-like  organs  on  their  noses,  made 
up  of  complicated  folds  of  skin  overlying  processes 
of  gristle.  The  body  is  covered  with  soft  hairs  whose 
surface  presents  a  peculiar  and  characteristic  scaly 
appearance  under  the  microscope,  and  the  fronts  of 
the  wings  are  extremely  sensitive.  They  rest  by 
hooking  on  to  branches  or  ledges  by  the  curved  claws 
of  their  hind  toes,  and  many  of  them  thus  feed  with 
their  heads  downwards.  They  are  extremely  awkward 
in  progression  on  the  ground,  and  rarely  resort  to  this 
method  of  locomotion.  Most  of  the  bats  of  temperate 
climates  hybernate,  and  these  are  almost  all  insecti- 
vorous, having  sharp-pointed  teeth  like  those  of  the 
Insectivora.  In  warmer  regions  of  the  New  World 
there  are  numerous  large  species,  such  as  the  vam- 
pires, which  are  suctorial  in  habit,  sucking  the  blood 
of  large  animals,  for  which  purpose  they  have  sharp 
lancet-like  teeth,  and  a  long  suctorial  stomach.  In 
the  tropics  of  the  Old  World  there  are  the  largest 
individuals  of  the  order,  the  fruit  bats  or  Pteropi, 
which  inhabit  the  Asiatic  and  insular  shores  of  the 
Indian  Ocean.  They  have  blunt  teeth,  moderate  ears, 
and,  in  one  species,  the  distance  from  tip  to  tip  of 
the  wings  is  often  as  much  as  five  feet.  They  are 
sometimes  called  flying  foxes,  from  their  prevailing 
colour  and  the  shape  of  their  heads. 


Ii8  Vertebrata. 

CHAPTER  XIX. 

MONKEYS.      MAN. 

70.  Order  16,  Primates.  —  This,  the  last  and 
highest  order  of  mammals,  includes  the  most  highly 
organised  members  of  the  entire  animal  kingdom  —  • 
the  monkeys,  apes,  and  mankind.  They  all  possess 
opposable  thumbs  on  some  of  the  extremities,  and 
(except  among  the  marmosets)  flat  nails  in  place  of 
claws.  The  face  is  mostly  naked  though  fringed  with 
hairs.  The  teeth  are  of  three  kinds  and  thirty-two 
in  number,  the  formula  being  usually 


2—2  I  —  I  2—2  3—3 

They  have  the  highest  proportional  development  of 
brain  of  all  animals,  and  the  fore-limbs  are  chiefly  set 
apart  to  wait  on  the  head.  There  are  four  sub-orders 
included:  — 

1.  The  marmosets  of  South  America,  gregarious 
small  monkeys  of  a  squirrel-like  habit,  which  have 
sharply  tubercled   teeth,  claw-like   nails   on  all   the 
digits,  except  the  great  toe,  which  alone  bears  a  flat 
nail.     The  long  fur-clad  tail  is  incapable  of  grasping, 
and  the  thumb  is  scarcely  opposable. 

2.  The  American  monkeys,  which  differ  from  all 
others  in  having  an   additional  premolar  tooth  on 

each  side  of  each  jaw  (P  $  —  -  j.     They  have  for  the 

O        O 

most   part   prehensile  tails,  and   the   thumb   of  the 


Monkeys.  119 

hand  is  not  well  developed,  or  is  absent  as  in  the 
spider  monkeys  :  on  all  their  fingers  they  have  thick 
convex  nails.  Most  of  these  live  in  the  woods  of 
Brazil,  and  are  found  in  troops.  The  howling 
monkeys  have  a  drum-like  enlargement  of  the  tongue 
bone  at  the  top  of  the  larynx  or  organ  of  voice,  and 
with  it  they  can  produce  a  loud  booming  sound, 
audible  for  nearly  a  mile.  In  all  the  American 
monkeys  the  nostrils  are  separated  by  a  very  broad 
partition,  their  ear-drums  or  tympanic  bones  in  the 
skull  have  also  wide  oval  mouths. 

3.  The  Old  World  monkeys  and  apes  are  charac- 
terised by  having  a  narrow  nasal  septum,  and  the  ear- 
drums have  a  long  tubular  mouth.  The  dentition  is 

similar  to  that  of  man,  the  premolars  being  -  — 2. 

2 2 

They  have  almost  always  an  opposable  thumb  on  the 
hand  as  well  as  on  the  foot,  though  it  is  rarely  as 
perfect,  and  the  muscle  which  bends  it  is  never  sepa- 
rate from  the  common  flexor  muscle  of  the  other 
fingers.  The  baboon  family  may  be  known  by  pos- 
sessing cheek  pouches,  and  callous  patches  whereon 
they  sit,  as  well  as  by  their  elongated  jaws.  The  true 
baboons  have  dog-like  muzzles  and  very  short  tails  ; 
they  are  confined  to  Africa  and  Arabia,  and  some  of 
them  have  curiously  coloured  faces;  thus  the  mandrill, 
with  its  blue,  deeply-grooved  cheeks,  its  brilliant 
scarlet  lips  and  nostrils,  and  its  white  beard,  is  a 
most  striking-looking  creature.  Some,  like  the  Bar- 
bary  ape,  the  only  species  which  now  lives  in  Europe, 
have  no  visible  tails  ;  others,  like  the  cercopitheci  or 
green  monkeys,  have  long  tails,  but  these  organs  are 


120 


Vertebrate. 


FIG.  58. 


Skeleton  of  siamang. 


never  prehensile. 
Many,    like    the 
macaques  of  East- 
ern    Asia,     have 
long  and  promi- 
nent canine  teeth, 
but  these  are  wea- 
pons of   offence, 
not  indicative  of 
a  carnivorous  diet. 
The  sacred  mon- 
key of  India  (Sem- 
nopithecus),      and 
the       thumb-less 
Colobus  of  Africa, 
have    no    cheek- 
pouches,  but  pos- 
sess long  tails  and 
callosities,    while 
the  highest  group 
of  the  sub-order, 
the  so-called  an- 
thropoids,     have 
no    tails,   callosi- 
ties,   nor    cheek 
pouches.      The 
chimpanzee   is  a 
black-haired  ape, 
a  native  of  Guinea, 
which  sometimes 
reaches  a  height 
of  five  feet.    The 


Man.  121 

orang-utan,  a  larger  brown-haired  species,  with  longer 
arms  and  a  larger,  rounder  head,  is  found  in  Borneo 
and  Sumatra.  The  gorilla,  the  largest  of  the  anthro- 
poids, is  a  native  of  Senegambia,  and  is  nearly  as  tall 
as,  but  much  stouter  than,  a  man.  The  gibbons  of 
Southern  Asia  differ  from  the  anthropoids  in  having 
callosities,  and  resemble  the  orangs  in  the  enormous 
length  of  their  arms  (fig.  58). 

4.  Man  is  the  last  and  highest  type  included  in 
the  order,  and  though  in  an  anatomical  point  of  view 
there  are  not  a  sufficiently  numerous  series  of  differ- 
ences of  kind  to  lead  us  to  form  of  him  a  separate 
order,  yet  there  are  enormous  differences  of  degree, 
even  of  such  kinds  as  are  cognisable  by  the  zoologist, 
who,  from  the  difficulties  incident  thereto,  cannot 
easily  take  psychological  considerations  into  account 
in  constructing  a  classification. 

Man  has  a  rudimentary  (though  an  almost  com- 
plete) hair  clothing,  and  a  perfectly  opposable  thumb 
on  the  hand,  moved  by  independent  muscles,  while 
the  great  toe  is  only  capable  of  grasping  by  approxi- 
mation, not  by  opposition,  and  even  this  power, 
though  great  in  some  savage  tribes,  is  almost  des- 
troyed, in  civilised  races,  by  the  habit  of  wearing 
shoes.  The  arms  in  man  are  shorter,  and  the  hind 
limbs  longer  and  stronger  than  in  any  of  the  apes. 
Progression  is  bipedal,  and  the  feet  are  plantigrade, 
while  the  arms  are  specially  and  solely  set  apart  for 
waiting  upon  the  head.  The  muscles  which  keep 
the  body  erect,  such  as  those  of  the  back,  the  ex- 
tensors of  the  hip-joint,  and  the  muscles  of  the  calf 
are  enormously  greater  than  are  the  corresponding 


122 


Vertebrata. 


FIG.  59. 


parts  of  monkeys,  while  the  spinal  column  exhibits  a 
series  of  curves  so  constructed  that  the  centre  of 
gravity  falls  between  the  feet.  The  brain  of  man  is 
larger  in  relative  size  and  complexity  than  t'uat  of  any 
other  animal,  being  on  an  average  fifty  ounces  in 
weight,  while  that  of  the  orang-utan  weighs  only  about 
sixteen  ounces.  Man  is  also  capable  of  articulate 
speech,  and,  psychologically,  man  is  susceptible  of 
education,  which,  in  kind  as  well  as  in  degree,  is 
utterly  unknown  among  the  lower  animals. 

Man  also  is  capable  of  fitting  himself  for  residence 
in  any  climate,  and  having  been  thus  long  scattered 

over  the  face  of  the 
earth,  the  single 
human  species  pre- 
sents to  us  numerous 
varieties,  none  of 
which,  however,  ex- 
hibit any  approach  to 
true  specific  distinct- 
ness. These  varieties 
may  be  classed  as 
follows : 

i.  Woolly-haired 
races,  such  as  the  Negroes,  Andamanese,  and  the 
Negritos  of  the  Malay  Archipelago. 

2.  Straight-haired  races,  which  may  be, 
a.  Australioid  or  dark-skinned,  small-headed 
races,  such  as  the  aborigines  of  Australia,  the  abo- 
riginal or  hill  tribes  of  India  and  Ceylon,  possibly  the 
ancient  Egyptians,  and  the  aboriginal  races  of  the 
stone  age. 


Skull  of  negro. 


Man.  123 

b.  Turanian  races,  yellow  or  red-skinned,  mostly 
broad-headed  races,  like  the  Mongols,  Chinese,  the 
American  Indians,  &c. 

c.  Iranian  or  Indo-Germanic  races,  pale  or  olive 
races,  usually  bearded,  and  usually  with  longer  heads 
and  straighter  features. 


INDEX  AND  GLOSSARY. 


ABO 

A  BOMASUS,  the  fourth  stomach 
**     in  ruminants,  96 
Acanthopteri,  spiny -finned  fishes,  30 
Accessory  eyes  in  Scopeline  fishes, 

29 

Acrania,  headless  vertebrates,  5 
sEfyomis,  a  gigantic  extinct  bird  ot 

Madagascar,  62 
African  mud-fishes,  14-33 
Aftershaft,  53 
Air  in  bones  of  birds,  57 
Albatross,  72 
Allantois,  a  membrane  surrounding 

the  young  of  reptiles,  birds,  and 

mammals  before  birth. 
Alligators,  52 
Alula,  the  bastard  wing,  or  feathers 

borne  on  the  thumb  in  birds,  54 
Alveoli,  the  sockets  of  the  teeth  in 

vertebrate  animals, 
A  mblyopsis,  or  blind-fish,  29 
American  monkeys,  118 
Amphibia,  34 
—  blood  of,  36 
Amphicoelous  vertebrae,  bones  of  the 

vertebral  column  which  are  hollow 

on  both  surfaces,  15 
A  mphioxus  lanceolatus,  4 
Amphiuma,ont  of  the  amphibia,  39 
Anacanthini,  soft-finned  fishes  with 

no  swimming  bladder,  29 
Anal  fin,  14 

Anatomy  of  amphioxus,  4 
Angutsfragilts,  43 
Animals,  vertebrate,  characters  of,  x 
Anteaters,  80-85 
Antelopes  100 
Anthropoid  apes,  zao 


BAB 

Anura,  tailless  amphibians,  such  as 

frogs,  39 
Aorta,  the  large  bloodvessel  which 

conveys  the  pure  blood  from  tha 

heart,  21 
Aortic  arches,  9  ;  in  reptiles,  40  ;  in 

birds,  60  ;  in  mammalia,  78 
Aplacentalia,  such  mammals  as  have 

no  placentas. 
Apteryx,    wingless   bird    of    New 

Zealand,  63 
Arch,  neural,  3 
Arch,  hyoid,  8 
Arches,  aortic,  9 

—  branchial  or  gill,  18 

—  visceral,  7 
Armadillos,  86 

—  scales  of,  74 
Arterial  cone  in  fishes,  2 
Arteries,  branchial,  21 
Articulation,  a  joint  between  two 

bones. 

Artiodactyla,  even-toed  hoofed  ani- 
mals, 93 

Asymmetry  of  flat-fishes,  31 

Atlas,  the  first  bone  of  the  vertebral 
column,  which  supports  the  head. 

Atrium  in  amphioxus,  4 

Auricle  of  heart,  9 

Australioid  races  of  man,  122 

Aves,  birds,  52 

Axolotl,  a  Mexican  amphibian,  40 

Aye  Aye,  113 


T5ABOONS,  119 

*J    Babyroussa,  a  kind  of  pig  from 
the  Malay  Islands,  94 


126 


Index  and  Glossary. 


BAD 

Badger,  104 
Barbary  ape,  119 
Barbel,  a  river  fish,  28 
Basking  shark,  25 
Bats,  115 
Bears,  104 
Beavers,  108 
Bee-eaters,  64 
Bile,  9 
Birds,  52 
Bitterns,  71 
Blackbird,  66 
Blackcap,  67 
Blennies,  31 
Blind  amphibians,  37 

—  fishes,  29 

—  rats,  109 

—  worms,  43 

Blood  of  amphibians,  36 

—  of  fishes,  21 
vertebrates,  9 

—  corpuscles  of  fishes,  22 
of  birds,  61 

—  vessels  of  birds,  60 
of  fish-gills,  20 

Blowing  and  blowholes  of  whales, 

99 

Boa,  8,  46 

Body  of  vertebrate  animal,  2 
Bones,  formation  of,  17 
Bony  pike  of  California  (Lepidos- 

teus),  27 

Bony  skull,  7,  17 
Bottlenose  whales,  101 
Box  fishes,  32 

Bradypoda,  the  sloth  family,  88 
Brain  of  cod,  19 

craniota,  19 

fishes,  19 

Branchial,  pertaining  to  the  gills. 

—  arteries  of  fishes,  21 
Breathing,  10-35 
Bullfinch,  67 
Bullhead,  31 

Bunodonts,  hoofed  animals  with  tu- 

berculated  teeth,  93 
Bustard,  71 
Buzzard,  69 


pADUCOUS   gills,    gills    which 
^     fall  off  before  the  animals  reach 

maturity. 
Caecum,  the  first  part  of  the  large 

intestine. 
Caecilians,  worm-like  amphibians,  37 


COB 

Calamoickihys,  African  reed  fish,  27 

Callophis,  snake,  poison  gland  of,  48 

Camels,  96 

Canine  teeth,  the  eye-tooth,  the 
foremost  tooth  in  the  maxillary 
bone,  when  it  is  single-fanged, 
and  the  corresponding  tooth  in 
the  lower  jaw. 

Carapace,  the  upper  shield  of  a  tor- 
toise, 49 

Camivora,  flesh-eating  mammals, 
102 

Carp,  28 

Cannate  birds,  those  with  a  keel  on 
the  breast-bone,  63 

Carotid  arteries,  neck  bloodvessels, 
78 

Carpus,  the  bones  of  the  wrist-joint. 

Cartilage  bones,  such  as  begin  their 
existence  as  masses  of  gristle,  17 

Cassowary,  62 

Catarrhine  monkeys,  old  world  mon- 
keys with  a  narrow  partition  be- 
tween the  nostrils,  119 

Cats,  103 

Cave  amphibians,  38 

Cave  bear,  106 

Cavities  in  the  vertebrate  body,  2 

Cebus,  South  American  monkeys, 
118 

Cephalic,  pertaining  to  the  head. 

Cephalisation,  subordination  in  func- 
tion of  limbs  to  the  head,  n 

Ceratodus,  Australian  fish,  34 

Cercopithecus,  green  monkeys,  up 

Cere,  soft  skin  at  the  base  of  the 
horny  beak  in  birds,  68 

Cerebrum,  the  greater  or  anterior 
lobes  of  the  brain,  20 

Cetacea,  whales,  99 

Chameleons,  44 

Cheetah,  hunting  leopard  of  India, 
104 

Cheiroptera,  115 

Chelonia,  tortoises  and  turtles,  49 

Chewing  the  cud,  95 

Chimpanzee,  120 

Chinchilla,  109 

Ciconite,  storks,  74 

Circulation  in  fishes,  20 

Civets,  104 

Clavicle,  the  collar-bone. 

Claws  of  cats,  icn 

Cloaca,  the  cavity  into  which  the 
intestine  and  excretory  organs 
open,  79 

Cobra,  hooded  snake,  asp,  48 


Index  and  Glossary. 


127 


coc 

Coccygomorfifue,  the  cuckoo  order 
of  birds,  64 

Coccyx,  the  rudimental  tail  in  the 
higher  mammals. 

Cockatoos,  64 

Cod,  17,  18,  29 

Collocalia,  the  swallow  which  se- 
cretes the  'edible  bird's  nest,'  65 

Colobusy  120 

Colossochelys,  a  giant  extinct  tor- 
toise, 51 

Colubrine  snakes  (non-poisonous), 
46 

Concentration  of  segments  charac- 
teristic of  vertebrates,  10 

Condyles,  knobs  of  bone  by  which 
one  bone  forms  a  joint  with  an- 
other, 38 

Contour  feathers,  the  strong  quill- 
feathers  on  the  surface  of  a  bird,  53 

Coots,  71 

Coracoid  bone,  one  of  the  bones  of 
the  fore  part  of  the  shoulder- 
girdle,  56,  79 

Coral  snake,  48 

Cormorants,  73 

Corncrake,  71 

Corpuscles,  microscopical  bodies 
found  floating  in  blood. 

—  of  blood  in  amphib  a,  36 

birds,  61 

iishes,  22 

Corvidte,  the  crow  family,  67 

Cows,  97 

Coypu,  109 

Cranes,  71 

Craniota,  skull-bearing  vertebrates, 

Cranium,  the  skull  of  a  vertebrate 

animal,  7 
Crocodilia,  51 
Crows,  67 
Ctenoid    scales,    fish-scales  with   a 

comb-like  hinder  edge,  14 
Cuckoos,  64 
Ciir^ica,  black-caps,  67 
Cuticle,  the  outer  layer  of  the  skin. 
Cycloid  scales,  thin  bony  fish-scales 

with  a  smooth  rounded   margin, 

13 


P)AB,  flat-fish,  30 

*-/     Dasypeltis,  snake,  teeth  in  the 

gullet  of,  48 
Dasyurus,  Tasmanian  devil,  81 


EEL 


Dasypus,  armadillo,  87 
Deer,  98 

Dental  formulae,  77 
—  formula  of  cat,  103 

dog,  103 

horse,  91 

kangaroo,  84 

man,  78 

marsupials,  84 

pig,  94 

ruminants,  98 

seal,  102 

sloths,  89 

Tasmanian  devil,  77 

Dentine,    the    ivory    substance    o' 

teeth,  13,  25 
Dentition,  the  arrangement  of  teeth 

in  an  animal. 
Dennis,  or  true  skin,  of  fishes,  12 

— rei  tiles,  40 

Diaphragm,  the  muscular  partitior 

between  the  cavity   of  the  chesi 

and  that  of  the  abdomen,  60,  78 
Digestive  system  of  birds,  58 

frogs  and  tadpoles,  36 

— ^ sharks,  25 

Diphycercal    tails,     tails    in    fishes 

with  an  even  marginal  fringe  of 

fin  rays. 
Dipnoi,     fishes     whose     swimming 

bladder  acts  as  a  breathing  organ, 

Diprotodon,  giant   fossil  kangaroo, 

84 
Dipus,  the  jerboas,  or  jumping  rats, 

109 
Dodo,  the  extinct  gigantic  pigeon  of 

Madagascar,  69 
Dog,  103 
Dog-fishes,  15,  26 
Dolphin,  101 
Domestic  fowl,  70 
Dormouse,  108 
Dorsal  fin,  14 
Doves,  69 
Dragon,  43 
Ducks.  72 
Dugong,  89 


RAGLES,  68 

*-*     Ear  passage,  nature  of,  8 

Echidna,     the    spiny     anteate     < 

Australia,  79 

Edentata,  toothless  mammals,  85 
Edible  birds'  nests,  65 
Eels,  28 


128 


Index  and  Glossary. 


EGG 

Egg  cases  of  sharks,  25 

Egg  pouches  of  pipe  fishes,  32 

Eggs  of  birds,  65 

fishes,  22 

Elasmobranchs,  sharks  so  called  from 

their  laminar  gills,  23 
Electric    organ    of  gymnotus,    the 

electric  eel,  28 

malapterurus,  28 

mormyrus,  28 

torpedo,  26 

Elephants,  no 

Embryonic  characters  in  vertebral 

column  of  sharks,  24 
Embryos  of  flat  fishes,  30 
Emus,  62 
Enamel,  the   hardest  portion  of  a 

tooth,  formed  by  the  calcification 

of  the  outer  layer  or  epidermis  of 

the  tooth  papilla. 
Epidermis,  or  surface  layer  of  the 

skin  of  fishes,  12 
—  of  reptiles,  40 

Equus,  the  horse  and  ass  genus,  91 
Ermine,  104 

Erythacus,  robin  redbreast,  67 
Exoskeleton,  bony  deposits  in  the 

skin  or  surface  tissues,  14 
Extensor,  a  muscle  which  straightens 

a  joint. 

External  gills  in  sharks   and  am- 
phibians, 30 
Extinct  reptiles,  52 
Eye  of  amphioxus,  5 
Eyes  of  birds,  61 
snakes,  46 


TTALCONS,  69 

Fallow-deer,  98 
Fauna,  the  collective  name  applied 

to  the  animals  of  a  country  or 

district. 
Feathers,  53 
Feeding  of  whales,  100 
Feet  of  birds,  59 
Felida,  103 
Femur,  the  thigh-bone. 
Fieldfare,  66 

Fierasfer  (a  parasitic  fish),  30 
Filefishes,  32 
Finches,  67 
Fin  rays,   the  bony  filaments  and 

spines  which  are  included  in  the 

fins  of  fishes. 
Fins  of  fishes,  14-19 
Fish,  epidermis  of,  12 


GIL 

Fish,  gills  of,  8 

—  head  of,  17,  1 8 

—  lateral  line  of,  15 

—  notochord  in,  17 

—  scales  of,  12 

—  shape  of,  12 

—  tail  of,  12-15 

Fistularia,  or  tobacco-pipe  fish,  3 
Flat  fishes,  30 
Flounders,  30 
Flying  fishes,  32 

—  foxes,  117 

—  lemurs,  115 

—  squirrels,  107 
Forelimbs,  114 
Fossil  amphibians,  37 

—  edentates,  87 

—  elephants,  112 

—  fishes,  27 

—  horses,  91 

—  mammals,  78 

—  reptiles,  52 
Fowls  domestic,  70 
Fox,  103 

Freshwater  and  marine  fishes  con- 
trasted, 22 

—  seals,  101 
Frigate  birds,  73 
Frilled  lizards,  43 
Fruit  bats,  117 

Fry  of  salmon,  tail  of,  15 
Functional,   capable  of  performing 

any  duty,  or  of  being  useful  in  the 

economy. 
Furculum,     the    merrythought    of 

birds,  56 
Fur  seals,  102 

C*  ANGLIA,  masses  of  nerve  mat. 

^-*    ter,  19 

Gannets,  73 

Ganoid  fishes,  fishes  with  burnished 

scales,  27 
Gar  pike,  32 
Gavials,  52 
Geckos,  43 
Geese,  72 

Gibbons,  long-armed  apes,  xax 
Gill  arches,  8-18 

—  cover,  19 

Gills  of  amphibians,  41 

—  —  fishes,  20- 2 1 

ganoids,  27 

lampreys,  24 

pipe-fishes,  32 

sharks,  25 


Index  and  Glossary. 


129 


GIL 

Gills  of  teleosts,  29 

Giraffes,  98 

Girdles  of  limbs,  8 

Gizzard,  the  muscular  stomach  of 

birds,  39 
Globe  fishes,  32 
Glutinous  hag,  23 
Gnawing  animals,  106 
Goat,  98 
Goatsucker,  65 
Gobies,  31 

Golden  pheasant.  70 
Goldfish,  28 
Gorilla,  121 
Grallce,  wading  birds,  such  as  cranes 

and  herons,  70 
Greek  tortoise,  51 
Grey  rat,  109 
Grizzly  bear,  106 
Grouse,  70 
Guillemots,  73 
Guinea  pig,  108 
Gulls,  72 
Gurnards,  31 
Gymnophiona,   caecilians,   or   blind 

amphibians,  37 

Gymnotus,  the  electric  eel,  28 
Gyrantes,   the  name  given  to  the 

pigeon  order,  69 

TLJADDOCK,29 

L     Hag,  glutinous,  23 
Hair,  74 
Halibut,  30 
Hallux,  the  great  toe 
Hammer-headed  shark,  26 
Hares,  108 
Harrier,  69 
Hawfinch,  67 
Hawk,  67 

Hawksbill  turtle,  51 
Head,  ii 

Hearing,  organ  of,  6 
Heart  of  amphioxus,  4 

birds,  59 

crocodiles,  51 

dipnoi,  33 

fishes,  21 

ganoids,  27 

mammals,  78 

manatees,  go 

reptiles,  41 

—  —  sharks,  25 

teleosts,  27 

Heat  of  birds,  61 
Hedgehog,  114 


JAW 


Helen's  eel,  28 

Hemisphere  of  brain,  20 

Herons,  71 

Herring,  viscera  of,  28 

Heterocercal  tails,  fishes'  tails  in 
which  the  vertebral  column  is 
prolonged  into  the  upper  lobe  of 
the  tail,  15-25 

Hind  limbs,  8-18 

Hippopotamus,  94 

Hollow  horns,  98 

Holothurians,  sea  cucumbers,  in- 
habited by  fishes,  30 

Homocercal,  evenly  bilobed  fishes* 
tails,  15 

Honeycomb,  the  second  stomach  of 
ruminants,  96 

Hoopoe,  64 

Hornbills,  64 

Horned  owls,  68 

Horns  in  mammals,  98 

Horse,  91 

House  sparrow,  67 

Howling  ape,  119 

Humerus,  the  bone  of  the  arm. 

Humming  birds,  66 

Hump  of  camel,  96 

Hybernation,  winter  sleep,  109 

Hyenas,  104 

Hyoid  bone,  the  bone  which  sup- 
ports the  base  of  the  tongue. 

Hyracoidea,  the  order  to  which  the 
coney  belongs,  106 

Hyrax,  coney,  106 

TBIS,  71 

•*     Ide,  a  carp-like  fish,  28 
Iguana,  group  of  American  lizards, 

Ilium,  the  haunch  bone  or  side  of 

the  pelvis. 

Impeyan  pheasant,  70 
Incisor  teeth,  76 
Insectivora,  114 
Insessores,  perching  or  sparrow-like 

birds,  66 
Internal  gills,  39 
Intestine  of  shark,  25 
Iranian  races  of  man,  1*3 
Isinglass,  27 


TABIRU,  71 
J      Jackdaw,  67 
Jaguar,  103 
Jaw  arches,  7 


130 


Index  and  Glossary. 


JAW 


Jaws  of  fishes,  18 

mammals,  76 

marsupials,  84 

sharks,  24 

Jay,  67 

Jerboa,  109 

John  Dory,  30 

Jugal  arch,  bony  arch  in  the  skull 
from  the  outside  of  the  upper  jaw- 
to  the  base  of  the  joint  of  the 
lower  jaw  with  the  skull. 

Jugular,  pertaining  to  the  throat. 


•Lf  ANGAROO,  82 

*^     Kidney,  10 

Kingfishers,  64 

Kinkajou,  105 

Koala,  the  native  bear  of  Australia, 


T  ABYRINTHODONTS,     fossil 
•L*    amphibians  with  complex  teeth, 

37 

Lacertilia,  lizards,  42 
Lamellirostres,   ducks    and   geese, 

T  72 

.Lamprey,  17,  23 

Lancelet,  3 

Larks,  67 

Larynx,  the  organ  of  voice,  placed 
at  the  top  of  the  windpipe. 

Lateral  line  in  fishes,  15 

Leg  of  birds,  57 

Leiotrichous,  straight  haired,  122 

Lemmings,  no 

Lemur,  113 

Leopard,  104 

Lepadogaster,  31 

Lepidosiren,  mud  fish,  17,  31 

Lepidosteus,  the  bony  pike  of  Cali- 
fornia, 27 

Leptoptilus,  the  bird  which  yields 
the  Marabou  feathers,  72 

Liber,  the  third  stomach  of  rumi- 
nants, 96 

Limb  girdles,  8,  75 

Limbs  of  boas,  8 

frogs,  39 

whales,  100 

Linnets,  67 

Lion,  102,  103 

Liver,  3-9 

Lithe,  29 

Lizards,  8,  42 


MER 

Llamas,  96 

Longipennes  gulls  and  terns,  72 

Lophobranchii,    pipe-fishes   having 

tufted  gills,  32 
Lore,   the  space  between  the   eye 

and  the  angle  of  the  mouth  in 

birds  and  reptiles,  71 
Loris,  113 
Lump  fish,  31 
Lung,  31,  35,  37 
Lynx,  104 
Lyre-birds,  68 


TV/TACACUS,  macaques,  or  bonnet 

and  rhesus  monkeys,  120 
Macaws,  64 
Mackerel,  31 
Macrochires,     long-handed     birds, 

such  as  swifts  and  humming  birds, 

65 

Magpie,  67 

Malapterutus,  electric  organ  of,  28 
Malar  bone.     Sie  jugal  arch,  89 
Mammalia,    animals    that    suckle 

their  young,  74 
Man,  121 

—  tail  of,  75 

—  teeth  of,  78 
Manatee,  75-89 
Mandible,  the  lower  jaw,  55 
Mandrill,  119 

Manis,  the  scaly  anteater  or  pan- 
golin of  the  Eastern  tropics,  85 

Manyplies,  the  third  stomach  of  a 
ruminant,  96 

Marabou,  the  stork  which  yields 
ornamental  feathers,  72 

Marine  fishes,  32 

Marmosets  or  Oustitis,  118 

Marsipobranchii,  fishes  with  pouched 
gills,  as  lampreys,  23 

Marsupialia,  pouched  mammals, 
kangaroos,  80 

Marsupial  bone,  81 

Maxilla,  the  bone  which  forms  the 
chief  part  of  the  upper  jaw,  76 

Megatherium,  gigantic  fossil  sloth, 
89 

Melisuga,  66 

Membrane  bones,  17 

Menopoma,  American  gill-bearing 
amphibians,  39 

Merganser,  72 

Mermaid's  purses,  25 

Mermaids  89 


Index  and  Glossary. 


MER 

Merrythought,  56 
Metamorphosis  of  tadpoles,  35 

—  ehanges    in  form    taking   place 
during  the  processes  of  growth. 

Migration  of  birds,  73 
Milk,  74 

—  teeth,  77 
Mink,  104 
Minnow,  28 
Missel-thrush,  66 
Moa,  62 

Mocking-birds,  67 
Molar  teeth,  77 
Mole,  114 

Moloch,  spiny  lizard,  43 

Mongoose,  104 

Monitor,  43 

M onotremata,  an  order  of  mammals 
having  a  cloaca,  79 

Mormyrus,  electric  organ  of,  29 

Mother  Gary's  chickens,  72 

Moulting,  the  process  of  the  period- 
ical shedding  of  feathers,  54 

Mound  birds,  70 

Mouse,  108 

Mouth  of  whales,  100 
vertebrates,  3 

Mud  eels,  38 

—  fishes,  15,  33 
Mullets,  31 
Muscles  of  birds,  58 
Musk,  96 

—  deer,  96 

—  glands  of  crocodiles,  51 
Mustela  foina,  or  marten,  104 
Myrmecobius,  the  banded  ant-eater 

of  Australia,  84 


TNJARWHAL,  101 

•^     Nature  of  sense  organs,  6 

Neck,  9,  75 

Neural  arch,  3 

Newts,  39 

New  Zealand  parrots,  64 

Nightingale,  67 

Nitrogenised  waste,  10 

Nostrils  of  lamprey,  23 

Notochord,  the  gristly  rod  which 
exists  as  the  first  form  of  backbone 
in  the  earliest  stage  of  all  verte- 
brates, 2,  17,  28 

Numida,  head  of,  70 

Nuthatch,  68 


PEN 

OCCIPITAL     bone,     the     bone 

^  which  forms  the  back  of  the 
skull. 

Ocelot,  104 

CEsophagus,  the  gullet  or  food- 
passage  from  the  mouth  to  the 
stomach,  3,  59 

Old  world  monkeys,  119 

Operculum,  the  gill  cover  in  fishes, 
19,  28 

Ophidia,  snakes,  44 

Opisthoccelous,  vertebrate  bodies 
which  are  concave  behind  and 
convex  in  front. 

Opossums,  81 

Optic  lobes,  20 

Orang-utan,  121 

Omithorhynchus,  the  platypus  or 
duck-mole  of  Australia,  79 

Orycteropus,  Cape  ant-eater,  86 

Osprey,  72 

Ostrich,  58,  60,  64,  66 

Otter,  104 

Ounce,  103 

Oven-building  birds,  68 

Oviparous,  reproducing  by  the  ay- 
ing  of  eggs, 

Oyo  viviparous,  retaining  eggs  with- 
in the  body  until  they  are  hatched 

Owls,  68  Ox,  97 

Oyster-catchers,  71 

pANTHER,  103 
r      Pangolin,  86 

Papilla,  a  wart-like  projection  of  the 
dermis. 

—  feather,  54 
Paradise,  birds  of,  68 
Parasitic  fishes,  30 
Parasphenoid  bone,  the  long  bone  at 

the  base  of  the  skull  in  fishes,  36 
Parrots,  63 
Parrot  fishes,  32 
Partridges,  70 
Patella,  the  small  bone  or  'cap    of 

the  knee-joint. 
Paunch,  96 
Peacocks,  70 
Pecten,  a  structure  in  the  eye  of 

bird,  61 
Pectoral  fins,  19-26 

—  muscles  of  bird,  58 
Peewit,  71 

Pelias,  the  viper,  47 
Pelicans,  73 
Pelvis,  56,  81 
Penguins,  66,  72 


132 


Index  and  Glossary. 


PER 

Perch,  31 

Perching  birds,  66 

Perennibranchiate  amphibians,  40 

Peroneus  muscle  in  leg  of  birds,  58 

Petrels,  72 

Phalanges,  the  b  nes  of  th    ringers 

and  toes. 
Pharyngognathi,     wrasses,      fishes 

with  united  pharyngeal  bones,  32 
Pharynx,    the   uppermost    part   of 

•the  digestive  canal,  3 
Pheasants,  70 
Philomela,  nightingale,  67 
Phamzcjtra,  redstart,  67 
Physostomi,  fishes  with  a  swimming 

bladder,  28 
Pici,  woodpeckers,  64 
Pig,  93 
Pigeon,  69 
Pike,  28 

Pinnipedia,  seals,  101 
Pipa,  South  American  toads  which 

carry  the  young  on  their  backs, 

40 

Pipe  fishes,  32 
Pipits,  67 
Pisces,  fishes,  u 
Placenta,  85 
Placoid  scales,  12 
Plaice,  30 
Plantain  eaters,  64 
Plantaris  muscle  in  the  bird's  leg, 

58 

Plantigrade,  a  term  applied  to  ani- 
mals which  in  walking  place  the 

entire  surface  of  the  sole  of  the 

foot  on  the  ground. 
Plastron,    the    under    shield  of   a 

turtle  or  tortoise,  49 
Platypus,  79 
Platyrrhine,     American     monkeys 

with  a  wide  nasal  septum,  119 
Plectognathi,  sunfishes  whose  upper 

jaw-bones  are  soldered  together,  32 
Pleuronectidce,   flat-fishes,   such  as 

the  plaice,  &c.,  30 
Plovers,  71 
Poison-fangs,  47 
Poisonous  snakes,  47 
Polypterus,  Nile  ganoid  fish,  27 
Porcupine,  109 
Porpoises,  101 
Pouch  in  marsupials,  81 
Prehensile  tails,  75 
Premaxilla,  teeth  in,  77 
Premolar  teeth,  77 
Prey,  birds  of,  68 


ROA 

Primates,  118 

Proboscidea,  elephants,  no 

Pronghorn  antelope,  98 

Prosimii,  113 

Proteus,  38 

Protopterus,  the  African  mud-fishj 

Psittaci,  parrots,  63 

Pteropus,  fruit  bats,  117 

Pterygoid  arch,  55 

Pteryke,  tracts  of  strong  feathers  in 

birds,  54 
Puffin,  73 
Puma,  103 

Purses,  mermaids',  25 
Pygopodes,  penguins,  73 
Python,  6,  46 


QUADRATE  bone,  74 
X,     Quagga,  91 

T>  ABBIT,  108 

±v    Rachis,   the  central  axis  of  a 

feather,  53 

Radius,  the  outer  bone  in  the  fore- 
arm, 40 

Raptores,  birds  of  prey,  68 

Rasores,  scraping  birds,  poultry,  70 

Rat,  108 

Ratidez,  running  birds  with  no  keel 
on  the  breast-bone,  62 

Rat-mole,  109 

Rattlesnake,  47 

Raven,  67 

Rays,  26 

Razorbill,  73 

Rectrices,  the  strong  tail-feathers, 

Red  deer,  98 

Redstart,  67 

Reed-fish  of  Africa,  27 

Regulus,  wrens,  67 

Remora,  sucking-fish,  31 

Rennet,  96 

Reptiles,  40 

Respiration,  3,  22 

Restoration  of  lost  parts  in  reptiles, 

42 

Reticulum,  96 
Rhea,  62 
Rhinoceros,  92 
Rhinodon,  gigantic  shark,  a6 
Rhytina,  extinct  sea-cow,  89 
Ribs,  9 
Roach,  28 


Index  and  Glossary. 


133 


ROB 

Robin,  69 

Rodentia,  zo6 

Roebuck,  98 

Rollers,  64 

Rook,  67 

Rummantia,  animals  which  chew 

the  cud,  94 
Ruminating,  95 

CABLE,  104 

^    Sacrum,  the  united  vertebrae 

which  enter  into  the  pelvis,  75 
Saith,  fish,  29 
Salamander,  38 
Salicaria,  warblers,  67 
Salmon,  28 
Sawfish,  26 
Scales  of  amphibians,  39 

fishes,  12,  25,  28,  29,  32 

reptiles,  43 

Scapulars,  feathers  on  the  shoulder, 

Sclerotic  plates,  61 

Scopelidae,  accessory  eyes  of,  29 

Scraping  birds,  70 

Screw  propeller,  principle  of,  12 

Sea-cows,  89 

Sea-horses,  32 

Seals,  loz 

Sebaceous  glands,  74 

Segments  of  skull,  7 

body,  10 

Segmental  ducts,  10 
Selachia,  sharks,  24 
Semnopitheci,  120 
Sense  organs  in  tadpoles,  36 

6,  15 

Shape  of  fishes,  12 
Sharks,  7,  13,  17,  24,  25 

—  external  gills  of,  39 
Sheep,  98 

Shrews,  115 

Sieboldia,  giant  salamander,  39 

Siren,  mud-eel,  38 

Sirenia,  sea-cows,  89 

Skate,  26 

Skeleton  of  bird,  55 

1 fro?»37. 

• lepidosiren,  16 

• mammals,  75 

—  —  sole,  15 

—  ^ —  tortoise,  50 

Skin,  action  of,  in  respiration,  10 

—  of  amphibia,  34 
Skull,  6 

—  of  amphibian,  36 


TEA 


Skull  of  bird,  55 

elephant,  no 

fishes,  17,  18 

mammal,  75 

reptile,  41 

Skunk,  104 

Slits,  visceral,  3-6 

Sloth,  75,  88 

Smell,  20 

Snake-like  lizards,  43 

Snakes,  44 

Snipe,  72 

Sole,  15-29 

Song  thrush,  66 

Spalax,  the  blind  rat-mole  of  S. 
Europe,  109 

Sparrow,  67 

Species  offish,  number  of,  22 

Spermaceti,  101 

Sperm  whales,  101 

Spider  monkeys,  up 

Spiral  valve  in  shark's  intestine,  25 

Spoonbills,  72 

Squirrels,  108 

Stag,  98 

Starling,  67 

SteganoJ>odest  pelicans  and  cormo- 
rants, whose  fourth  toe  is  included 
in  the  web,  72 

Stickleback,  31 

Stomach  of  camel,  96 

ruminant,  95 

sheep,  95 

whales,  100 

Storks,  71 

Strigops,  the  New  Zealand  ground 
parrot,  64 

Sturgeons,  17,  27 

Sucking  fishes,  31 

Sunbirds,  68 

Sunfish,  32 

Swans,  72 

Swifts,  65 

Swimming  bladder  in  fishes,  22,  29 

Swordfish,  33 

Sylvia,  wood  warblers,  67 

Syrinx,  the  organ  of  voice  in  birds, 
61 


TADPOLE,  36-38 
A      Tails,  9,  15,  19,  78,  ioi 
Tapirs,  91 
Tarsius,  114 
Tasmanian  devil,  77,  81 
—  wolf,  Si 
Teal,  74 


134 


Index  and  Glossary. 


TEE 

Teeth,  10-14 

—  of  elephant,  in 

--  lamprey,  23 

--  mammals,  76 

--  rodents,  107 

--  snakes,  46 

Teguexins,  47 

Teleostet,  bony  fishes,  27 

Tench,  28 

Terns,  72 

Thorax,  the  cavity  of  the  chest,  8 

Thrushes,  67 

Thymus  gland,  no 

Tiger,  103 

Titmouse,  67 

Toads,  39 

Toes,  57,  82,  91 

Tongue,  8,  44,  45,  58,  79 

Torpedo,  27 

Tortoises,  49 

Toucans,  64 

Trabeculce,   processes  of  gristle  at 

the  base  of  the  embryo  skull,  7 
Trachinus,  weaver  fishes,  31 
Tree  frogs,  40 
Tropic  birds,  73 

Tropidonoust  the  ringed  snake,  46 
Trout,  28 
Trumpet  fish,  31 
Trunk  of  elephant,  in 
Tunicated  worms,  relation  of  to  ver- 

tebrates, 2 

Turanian  races  of  mankind,  123 
Turkey,  70 
Turtles,  49 

T  T  LNA,    the    inner  bone  of  the 
^     forearm,  40 
Ulotrichi,   woolly  haired   races    of 

man,  122 

Umbilicus  of  feather,  53 
Ungulates,  hoof-bearing  mammals, 


Uro 


rodela,  tailed  amphibians,  38 


53 


VAMPIRES,  117 
v      Vanes  of  feathers, 
Veins  of  the  liver,  3 
Vena  portse,  the  vein  that  carries 

th<:  blood  from  the  intestines  to 

the  liver,  3 


ZEB 

Venomous  snakes,  47 
Ventral  fins,  19 
Ventricles  of  heart,  9 
Vertebra,  one  of  the  detached  ele- 
ments of  the  backbone,  3 
Vertebral  column,  24,  29,  36,  41,  45 
Vertebrata,  characters  of,  i 
Vipers,  47 

Visceral  arches  and  slits,  3,  19 
Viscera,  organs  of  the  body. 
Vison,  104 
ViverridcB,  104 
Voice  in  birds,  60.  61 
Voles,  108 
Vultures,  68 

VXTAGTAILS,  67 
vv  Walrus,  102 
Warbler,  67 

Waste  of  living  bodies,  10 
Water  hens,  71 
Water  snakes,  48 
Wattles,  70 
Waxwings,  68 
Weasels,  104 
Weevers,  31 
Whalebone,  100 
Whales,  99 

—  limbs  of,  loo 

—  teeth  of,  76 
Wheatears,  67 
Whinchat,  67 
Whiting,  29 
Widgeon,  72 
Wild  cat,  104 

Wild  swan,  windpipe  of,  72 
Wings  of  bats,  117 
Wolf,  103 
Wombat,  84 
Woodpecker,  64 
Woodquest,  76 
Wrasse,  32 
Wren,  69 


yAPOCK,  82 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 


AN     INITIAL    FINE     OF     25     CENTS 

WILL  BE  ASSESSED  FOR  FAILURE  TO  RETURN 
THIS  BOOK  ON  THE  DATE  DUE.  THE  PENALTY 
WILL  INCREASE  TO  SO  CENTS  ON  THE  FOURTH 
DAY  AND  TO  S1.OO  ON  THE  SEVENTH  DAY 
OVERDUE. 


FEB  17  1933 


OCT 


(934 

1Q26 


139 


'6  28 


LD  21-50m-8,-32 


